It's good you're looking to do the prep work before painting. This is the hardest and probably most time consuming part of painting. Heck, almost anyone can paint. But can they do the prep work???
Anyway, I'll assume you're NOT painting newly hung drywall nor painting a light color over a dark one ... Soooo, I 'cut' the corners where walls and ceiling meet. Then I do the ceiling, then I do the walls. DON'T skimp on paint! Buy yourself some good paint from one of the renouned Paint Retailers (found in the Yellow Pages) like Finnaren & Haley, MAB, Sherwin-William, etc., etc.. Sometimes, 2 top coats are needed so be generous if you want to get by with 1 coat. (I, personally, do 2 coats.)
The last thing you do is the trim. Buy some Painters Tape (not Masking Tape), and 'cover' the baseboard trim with at least 2" wide tape. (You can tape a piece of plastic to part of the tape before you put it on the trim to protect the trim and the carpet/floor.) Of course, move and/or cover everything in the room being painted. I move what I can into the middle of the room, and cover it. I use a broom handle extension on my roller. Get good brushes and rollers. The cheap ones will show a 'bad' job.
Here's a linke Hometime Projects that has a Paint & Decorating link on it. It should prove useful.