1. Bill hourly.
2. Contracts will do you no good in the end. Only work with people and companies you trust.
3. Set small milestones. 1 - 2 weeks is preferable.
4. Know the technologies you are working with. Don't be a jack-of-all-trades-master-of-none.
5. Speak good English.
6. Always deliver on time.
"I know the every sperm is sacred types will whine about this"
FYI, sperm != human life.
"Wouldn't you prefer never to have existed if you knew you would be subjected to mental retardation, health complications, and a short lifespan"
What qualifications do you have to make this decision on behalf of others?
I'm a Lisp variable -- bind me!