Terms and Guidelines for commissions?

[mistystriker.livejournal.com]

A lot of artists and fursuiters seems to have Policies and Guidelines in regards to dealing with commissions posted on their websites. I think this is a great idea personally, simply because it keeps customers from assuming certain things and helps keep things simple. As long as you have a condition that people should reads the terms before commissioning you it could save so much trouble.
I'm planning on writing some for my own site and I was wondering whether there are specific things I should be sure to address. What are the most common problems you have run into in regards to commissions? How do you deal with them? What would you reccommend I add?

Help is personally appreciated and probably appreciated by others further along the line if others take on this idea.