MOST IMPORTANT TIP: make sure you have your story banged out.
And by that, I mean make sure you have the story aligned and a solid idea of where you want to go with the story, what you want to do with the characters, and how you want them to grow. You dont want to start making a comic and you havent scripted/plotted/outlined the story and now everything is going off the rails OR you hit a brick wall with development because you didnt plan for a thing.
Style isnt the "be all". You can develop a style over time...just make sure you're comfortable drawing the page/panel overall- once the style comes along it will make it a bit easier to work, but dont put that as the most important element. Make sure you capture shots from different angles(zoom out, close up, mid shot, perspective shots); that will help make things more interesting.
I cant even answer about not making my comic tedious, coz that seems to be my thing right now.
As for shortcuts/tips, I will agree with some of the other posts. Invest in & use 3-D apps/programs to help set up backgrounds and scenes- you want to work smarter, not harder. In fact, same rules apply when setting up character layouts as well; use 3-D character models to get that pose for that panel- it'll shave tons of scribbling extra lines & work off you. Also re-use background scenes if you can; def saves a lot of creative time and energy.
Dont use a font that you think "looks pretty" but is not designed for dialogue in comics; get something that is easy, clean, and readable.
Watch your colors(if you're coloring)- dont go TOO dark; when it uploads, it looks muddy/saturated as heck.