prep work, before painting Options

[jayi12-15psi]

I'm about to have my car painted and I would like to save a little cash by doing the prep work by myself. Is there a good place online to read a "how to" on prep work? I've never done to much body work, I've worked a little on fiberglass but nothing to big. My knowledge as of right now consists of:

Sanding the original paint down to the primer using 400 grit, do I just use regular sand paper for this? should I start with a lower grit and work my way up? Should I just use an electric palm sander? Also What is a "wet sand" I read it discussed in another thread.

I plan on taking all the trim off of it except the windows.

is there some kind of paint stripper I should use? Do I put on another coat of primer when I sand down to the stock primer?

Sorry for all the questions, thanks for reading.

[Junior]

if no body work needs to be done, block sand it with wet 600. Don't use a palm sander. If the paint is original, just the shine needs to come off. If its not original, hope that the previous paint job was done right. You can't miss any spots and you can't sand too much in one area because it'll cause low spots. The main difference between a good paint job and a bad one is the prep work.