Bryan Lee O'Malley giving you professional advice on how to draw and make your own comics, right here:
"1. Planning and note-taking varies from project to project. When you're starting out, the most important thing is to start drawing the comic and do as many pages as you possibly can. You will need to do a few hundred really bad pages before you can start getting to the good stuff (unless you're a genius). Don't get hung up on planning and story-bibles and stuff until you know for a fact that you can go ahead and draw a comic in the first place. You could spend years doing character designs and writing backstory, but it doesn't amount to anything if you never actually tell the story.
2. I draw my pages 7x11, because that way they fit in the scanner without me having to scan in pieces and stick them together in photoshop. It makes everything faster and easier. I buy 11x14 paper and cut it in half. A lot of people draw bigger. At this size, I'm reducing to about 70% to print, which is okay for me.
3. I ink with a brush and ink. I think if you're going to be serious about comics you should get some ink and some brushes or pen nibs and seriously learn how to draw with them. It takes some practice and dedication, both of which are important if you want to draw comics. (I can't draw with a nib because I've never taken the time to learn.) The kind of brush I use is a Winsor & Newton "Series 7", size 2. The ink I use is Koh-i-noor brand. I also use various markers for small details (not Microns though, I can't stand them).
4. You have to scan black and white artwork at at least 600 dpi (some say 1200 dpi). Scan it in greyscale, then adjust the levels (ctrl-L in photoshop) so the blacks are black and whites are white (some scanners do this automatically, but I wouldn't trust them). Keep the art at 600 dpi always. Save the file as a PSD if you're using layers. The final file should be converted to bitmap and saved as a tif (and make sure you save the final files separately from the working files). If you're using greyscales, they can only print at 300 dpi generally - so, basically, don't use greyscales unless you want your lineart to be fuzzy. (There's more to it than that, but I'm being brief.)"
Via Warren Ellis.
Here's some of his thumbnails (go read the LiveJournal entry for yourself):