1: Find your sprites. Trust me, you'll want lots of poses. The Shyguy Kingdom is a great place to start. If you are feeling adroit, you can edit sprites yourself... Background images are a lot harder to find than character sprites, though.
2: Copy paste works wonders. Trust me, you can easily make your comic look longer by copy-pasting each frame. It also becomes nice and consistant.
3: Zoom. This is great for pixel edits of sprites, and also for when you need exact precision to make things.
4: Make sure your plot develops well. Or, lack of plot. See, while graphics are nice, you need a good plot to make your comic interesting. Character degisn is a very important part to comic design.
Case in point: I myself am a horrible artist. I made a sprite comic a while back, though Find it here.
Good luck and happy designing!
~I.S.~