A while ago I posted a step-by-step series of my work process in making a comic page. They were very quick and concise, and I always meant to go into more details, and touch upon some issues comickers should be aware of. Here, then, is the extended version. If you have additional questions, feel free to ask (but if they're software-related, I'll only answer if you're already quite familiar with the software – sorry, teaching Photoshop isn't my call!)
More related info in my interview by `misskittyoooo
I keep toying with the idea of making a comic tutorial, but for one thing, it would be positively book-length, for another, it has been done masterfully several times, most recently by the wonderful Scott McCould, so it doesn't seem there's a point making another!