Unless I'm doing a really long comic, usually I draw everything out at once, fix everything at once, ink everything at once...etc.
I think that makes it fairly consistent for me.
Also, having a plan how your characters look, how a place is set up is really important in consistently too. Otherwise, you will keep changing the face ^-^
I use to work on different projects at the same time, with different styles and needs.
Indeed, switching styles is hard work but also a great practice about staying fresh and learn to jump on any theme "in the blink of an eye".
In my case, usually sketching 2-3 characters/poses (even on the same page I'm going to complete) is enough to set my brain on the style I want.
HINT: Don't confuse graphic style with your "personal touch". You can mimic a graphic style while staying true to yourself and recognizable by others.
I changed the format a couple of times, it's still confusing to some, but I do believe that's also because I am not an artist. I mean, I am trying to write a webcomic as a writer. I put too much effort in what is said and how everything is intertwined that I don't put much effort in the visuals.
Part of my own lack of consistency is that I've improved drastically over the past few years of drawing the comic. Going back and redrawing some old Chapter 1 pages, I notice that my characters started out looking one way, and over time changed dramatically as I got better at letting their personalities shine through.
On the whole, don't be afraid to experiment. Sooner or later, you'll hit your stride.
You could always draw character expression sheets so you can reference your own drawings. That way when a character has a certain expression you can see how you drew it before to keep things on model.
Im trying to stick with what i think works however that may change as i get older. I may find a new technique i like better then my old style. But importantly its all about having fun ^^
Early pages in my comic2, my style was sort of all over the place. Over time though I think my comic is sort of forming its own look and feel. I guess time is the only judge. I know I have A LOT of room for improvement, but at the same time I do know that the more I keep working at it the better it will get over time. Whether you yourself recognizes it or not, you comics over a period of time will definitely showcase your style.
I.... don't. Well, I've arrived at a consistent style of colouring and inking, created by habit and a need to be pretty quick about it - but if you're talking about characters looking the same in every panel, hahahahaha nope.
The way I sketch, ink and colour is just the way of sketching, inking and colouring that comes naturally to me, and I keep the character's costume designs fairly consistent by having turn-arounds of all of the important ones.
BUT - I have partial face-blindness. I can remember individual features of someone's face (like how their nose looks, or their eyebrows, or their jawline) but I can't, for the life of me, remember faces as a unit - as in, all those features assembled into a face all at once. So every time I draw a character, I have to re-assemble all those bits into a face in my mind as I draw them, and I have to draw a character literally hundreds of times before I have any hope of getting it right on the first go. And even then, it's still a challenge.
Another trick for keeping consistent that I use is that I work chapter by chapter. I sketch a whole chapter, then ink, then colour. Now that I've started posting, and therefore cutting into my page-buffer, I switch off a bit, inking a couple of pages to start with, and then going back and colouring one page, going ahead and inking one, going back and colouring one - and so on. Having everything sketched out like that helps me keep my pace and consistency up.
I HAVE THE SAME THING. PROSOPAGNOSIA. I thought this was perfectly normal, and was very puzzled when I saw police TV shows where they ask potential witnesses about the criminal's facial likeness. I was always like, "but how are you supposed to remember that unless you have superpowers?"
With my current comic, I have it relatively easy because the main character is of a minority race (white male, haha, but he's in a place where everyone else looks Asian). It's easy to make him look distinct with his big nose, sturdy jaws and butt chin. I even gave him huge bushy eyebrows to top it off!
Still took me a while to figure out how to draw him right, of course, but I think I've done well considering everything.
The weird thing is, once I took a portrait painting class (not much instruction though, just a time and place where you get to sit and paint a live model) and my paintings almost always nailed the model's likeness. I couldn't tell, but a lot of people commented on it.
THIS TOO! Well, I can't always do it this way; sometimes I'm not ahead enough to be sketching 10 updates ahead because I have to finish the next update, haha. But when I have the time, I definitely prefer it this way. At the very least, I like to get the thumbnails for the whole chapter done before doing any other work.
One other thing regarding consistency: often you're the only one to notice the inconsistencies. Even if they look glaring, other people may not really notice it. I believe in focusing on the basics before worrying about the style. Unless you're doing something drastic like switching from hard-lined B&W to lineless full color, you're probably fine. 
I can draw people accurately from reference! Either from life or from photographs - it's remembering them without the photographs, or once they've walked out of view, that's the challenging bit. And since characters only really exist in my head, and therefore HAVE no photograph for me to reference, it's really hard to hit a consistent look for them.
Funny how that works.
I'm currently 52 pages ahead of what I'm posting on Tapastic and Tumblr, 50 pages ahead of what's on Patreon, because I took the time to draw all of that before I launched the comic. I try to keep that buffer-size, just so that I can take the time I need to thumbnail and sketch the entirety of the next chapter before the current chapter runs out. Thumbnailing is one of the trickiest bits for me, since not only do I have to wrestle with page-layouts and the reading-order of speech balloons, I also do almost all of my actual writing - dialogues and all that - at the same time as the thumbnails.
I've kind of gotten over the block and am faster these days, but it used to be that thumbnailing 7 pages in a day was a lot for me.
My brain can't construct a real, three-dimensional face out of a face in a photo. Sadness :<
Could it be... Are you my long lost comicking twin? Because I write my dialogues by typing them straight into the PSD files of the thumbnails.
I had like 20 chapters completed from a first draft of the comic made last year. When I first launched the new version of the comic, I was expecting to only draw 25% new stuff and fill the remaining 75% with recycled bits from the first draft... Turns out most of the first draft is unusable because the writing is just so bad, and the new writing doesn't work with the old art. Which is how I ended up doing four times more work than I had expected, haha!
Hahaha! XD I do all of my thumbnails on paper, with pencils - I need to be away from the distractions of my computer when I thumbnail/write my comics, or else I end up killing time on Twitter or something. So I do the first draft of dialogue there, then I use Manga Studio 4EX to do full-sized digital roughs, with proper panel borders and all the dialogue. Having done THAT, I export as PSDs, switch over to Paint Tool Sai to do clean sketches (I like the way its brushes work better than MS4EX, and also its resizing/transform tool, which is a gift to someone who, like me, tends to draw heads too large or hands too small and whatnot), and THEN I switch over to Manga Studio 5 for inks and colouring.
... and all the while I poke at the dialogue and fix and change things and re-size speech balloons and stuff, right up until the moment I post it. >.< I am an eternal dialogue-fiddler. And also I have the most needlessly complicated work-process, but it works for me.
I think it's ok to not be super consistent. The good thing about webcomics is that you have freedom to develop your style and try new things. No one finished from the start Most people like seeing the development through the years, I've found. Just keep at it, and make sure you find the short cuts to draw the things you draw over and over again in a relaxed and fun way (for you, not for the audience), otherwise there's a risk you'd go crazy from the work load.
Create a 'style bible.'
This time around, your work can be experimental and you'll grow into the style your characters and setting will be rendered in once you hit the end run of your work. If you start something new and you want it to stay consistent throughout, you have to take time at the beginning and really put together a book that has all of the core components of your story - setting, characters and items. Then draw those items over and over again until you've trained yourself to do it with your eyes closed.
If you change styles mid-stream, you run the risk of upsetting your fan base. If you work for a larger entity like a syndicated cartoon, they have step by step approaches to drawing characters consistently, all the time, every time.
I have the same problem. One thing I love doing the most is experimenting. Every minute I can think of ways of doing things differently to the point of making the style inconsistent. I wonder if this is just a phase all creators go through somehow. Maybe I'm still in the stage of developing my own style? Idk. I hope readers don't find style inconsistency too off putting.
Looks fine to me! Do you think it is just because you have improved? You are using the same brushes and all, so you are doing what you can.
When I started my current comic it was my first foray into digital art. I got more comfortable with the process over time. You can tell, since I got much much better by chapter 3, and some small things even ended up getting tweaked as I drew and adjusted to the process and tools. Characters that I drew a lot before being introduced stayed consistent, yet the first two characters introduced changed a lot from page one up to until maybe chapter 4. I hadn't drawn them enough before the first page. After two years of the comic, I went back and touched-up the earlier chapters to fix glaring mistakes like skin-tones that were too light and confusing dialogue.
So just draw. A LOT. Keep notes on items, outfits, places, and maybe maps and floor plans of things you will draw often so you can draw them consistently.
You will always improve and change. Even pick up Ranma 1/2 or something, compare volume 30 to volume 1, and you will see a difference! Or Garfield. Ever look at his evolution over the years? Do what you can, embrace that you will change, and keep moving ahead.
I tend to draw overly-exaggerated expressions, to the point where their faces don't even hold their original shape and form anymore. 
I guess the thing to do is just repeatedly draw your characters until your hands "remember" how to draw them with all their details. Different angles, scribble different details specifically; it'll come to you eventually. ^^
To be perfectly honest. The only series I have is one specifically to take advantage of a lack of consistency. I don't really have a solid idea of what "my style" is. So I got the idea if I just start writing/drawing eventually I should get my barrings and level off once I find something I like. Or if I felt like it I could do a page based off someone else's style and see how it goes (not stealing their style, that'd be rude) and make changes based off what I enjoyed doing, and fix issues to improve upon my own character and backgrounds and stuff.
It sounded like a dumb idea at the time, and it still does a little. But it seems to be working
I didn't really try to make my style consistent, I just sort of drew until it was. Once you practice something enough, you remember how to draw it in roughly the same way. It's not completely consistent because you always have to allow for natural progression of your art, but I think if I look at the first page of my comic and the latest, it's clear that they're from the same work.
