If you've knocked out the sequential art or comic strip from Part 5--Sequence, you're halfway there!
The first thing you'll want to do is erase most of those pencil lines you created way back when--not using that kneaded eraser, but with the eraser tool. Open your document in Photoshop if you haven't already and, if you wish, reformat your sequential art. Would you like it two across in two across and two down? Four across? Four down? Draw a marquee around each panel and move them to a new document. This will be your art's new home.
Using the bucket tool, fill in the colors you wish. These can be bold colors or shades of gray. You can do the same for backgrounds--feel free to import an image or pattern (such as a brick wall, for example). Use whatever effects and layers you wish; if you've got a knack for them, this is the place to let 'em shine. Just avoid the temptation to let the effects overshadow your story or your art; the idea is to enhance your work, not make it the star of the show!
After you have the panel art of your dreams (or a close facsimile thereof), it's time to add the letters. You can do them by hand, or, for a more professional look, download a free or almost free font from Blambot. (Admit it--Microsoft's Comic Sans is so Windows 95.) Copy them over from the document you created earlier and resize them as needed, keeping them roughly consistent among the panels. The round marquee tool makes it easy to create word or thought balloons; with a bit of practice, you can make the text stand out. Another way to make the text pop is to convert the letters into outlines, although this is not necessary for these purposes.
As with your original drawing, once you have everything the way you want it, flatten your image for file formatting or export purposes. You're done!
Next time, we'll take a final look at thinking cinematically. Even if you still can't draw, it'll help you focus on how you see things and enjoy others' work more.