1. Read
this so you have a clue going into #2
2. Get a lawyer for the work contract and to cover your ass.
3. Document EVERYTHING. If you have a simple contract form, document exactly what fields are included, any conditional logic, where it gets sent, etc.
4. Your project scope will creep. When it does, change orders are required. Repeat #3.
5. Prepare to make enemies.
I was in almost the same shoes as you were last summer. If it wasn't for me insisting a signed contract before any real work began, I would have been in a lot of hurt. The money never really was there, the verbally agreed rate would not have been honored, the scope would have wildly swung all over the place.
Also, don't forget to consider just the development, but any type of warranty period, ongoing maintenance, hosting, support, etc. Also are you an employee, or is this just contract work. If it's contract and the rights to the work aren't explicitly signed over as part of the contract, YOU own the copyright even if they pay for an hourly rate. That can be used as part of your negotiations leverage.