1.) Come up with an idea. Like, "girl has space-adventures, also - robots." or "wouldn't it be neat if I took all this love I have for samurai movies and wandering-swordsmen-manga and made a comic like that, except with my own twist?"
2.) Let the ideas stew for months, possibly years.
3.) Pick one and decide to actually DO IT.
4.) Scribble and plan and change my mind and plan some more and change my mind again. This is where all of the first-draft stuff happens - the initial character designs, the general outline, the writing down of cool ideas I might wanna use along the way.
5.) Having assembled the general shape of the idea and the outline, pick up said outline and start at the beginning. Pick enough plot-points from it to make up a chapter, and start breaking those down into more detail. What is going to happen in this chapter, in which order, and why? Who is going to be in it? Where is it going to lead? Write down a proper summary.
6.) Take the summary and break it down even further into more detail, going page by page. Like - "page one; main character A travels through a forest. Page two - main character A is startled by bird, and spots some broken twigs on a branch. Page three - main character A leaves the path to investigate" - etc., etc. Until I have a page-by-page breakdown of the entire chapter.
7.) STORYBOARDS AHOY!
These are of a Christmas-comic I did last year. I always do my storyboards on paper, because the internet is too distracting and would ruin things if I did it digitally. This is where I plan all of my page-layouts, and see if my page-by-page breakdown works, or if I need more - or less! - pages to tell my story.
Also, my thumbnails are approximately two inches tall, and all those scribbly little words beneath the thumbs are me writing the first draft of the dialogue - and sometimes tiny notes to myself re: what's happening on the page, to make my stick figures a bit easier to understand. And yes, this is the first time in the process in which I write any kind of dialogue. There may be a few stray sentences in the outlining process, but this is where the actual dialogue happens.
8.) Digital drafts!
These I do in Manga Studio EX4, creating a multi-page document with as many pages as the chapter needs. This is the thumbnail view, but these are all full-sized pages, on which I scribble all the rough sketches and place all of the speechbubbles+dialogue, so I know how much actual space they take up and if I need to change anything.
This is as detailed as my roughs ever get, and this is on the high end of the scale - usually, it's just full-size stick figures with frowny eyebrows (this example isn't from Grassblades - it's from a oneshot I did for an anthology in late 2013)
9.) Clean sketches. Next verse, same as the first - clean up the sketches and make them something that's possible to ink - although I have been known to ink right on top of my rough sketches, if they're good enough.
10.) Finishing. Inking, colouring, tinkering with lighting. Also, tweaking dialogue and getting rid of awkward phrasings and stiff wording and placeholder sentences. This step is 100% Manga Studio 5.
11.) Put it in the buffer. Then wait, like, 5-6 months until it's time to post it because I'm so far ahead of my readers. XD