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?
"Protozoa are small, and bacteria are small, but viruses are smaller than the both put together."