Masking....if there is any chance you may have to sand, whether it's from mistakes, blow throughs, or even residue from the masking tape itself, just put a light coat or 2 of a basecoat type clear (Intercoat clear) on your part first. Then scuff lightly with Scotchbrite pads, and proceed to masking and painting. You also need to do this if you are going over a pearl or metallic color.. tape might pull up the flakes. I even do this multiple times, if painting time is going to be long, or the next day, or it's a complicated design.
Pulling masking tape off: for the most part, you'll be using fast dry basecoat, lacquer, or intercoat clear to do graphics. They dry quickly, so just wait 15 min. or so and pull the tape, it will be dry. Thin, dry paint is brittle, and will break cleanly. The only time you want to try and pull tape off while the paint is wet, is when using slower drying enamels. This is so the edge has a chance to "heal", or settle down after pulling the tape. The softer, thicker enamels will bridge over the tape if left to dry too long, and you'll have problems removing it, unless you score the edge with a razor blade first.