1. Don't expect to be rich and famous.
2.Depending on the rules of the Faire, try to stick with period stuff. Check out Dowland, Playford and low number Child Ballads.
3.Check with each Faire, but in general even if you are getting paid, put out a "salted hat".
4.Always READ contracts.
Have fun and don't sweat the small stuff, it's hot enough in Renn. garb!