I'd like to replace my volume and tone knobs but I'm nervous about screwing up my guitar because they won't come off easily. Is there a special way to do it or should I pull harder?
You are talking about the plastic knobs that don't have a locking screw right? If so, a trick I've used is getting a couple credit cards, and slowly working the knobs up from each side using the cards.
Put a cloth on your guitar and use two spoons to lever up on the knob.
Shove a heavy guitar pick under there. Always does the trick for me.
just pull harder
Best thing to do is put a cloth on your guitar to protect the body and it's finish, and grab a small enough screwdriver, and get it under, and pull up. It'll take it off.