I just got a job for a small project. I have all the relevant skills and knowledge to complete the project, but I am concerned about getting screwed over because this is my first time working on a consultant basis. We have already agreed on an hourly wage that I'm happy with, so that's not an issue. I'm just worried that since this is my first time working on my own, I'm going to make some mistakes that could be easily avoided if I had someone give me advice beforehand. This is what I already know to do/not do:

-Get everything in writing
-Limit the scope of the project. Once I start the actually coding, all features should be frozen.
-Make sure to communicate constantly with my client.

In addition he wants an max hourly cap. What is a good way to come up with one?

What else do I need to know?