My pet peeve is don't sign anything before you've read it in it's entirety.

Once you've read it, read it again, and make sure you understand it.

If you don't understand it(them), then take a copy(ies) of the document(s) to your attorney and make sure he/she explains it to you before you sign it.

However, in most cases if you don't understand it, just don't sign it, especially if you can't afford to hire an attorney.

If you do nothing, you won't get harmed by the thing you didn't sign.