Keep your home office and computer separate from the rest of your life. Pay your quarterly taxes on time. Understand the difference between an employee and subcontractor. Subcontractors Remember that if they screw up, YOU lose. Hold people to their end of the bargain, but when talking to the client, accept all responsibility for what your subs do.
Good subs are hard to find.
Pay a good one well. Don't let subs talk to the client unless absolutely necessary. Keep in mind who hired who. Networking still works better than an ad in the paper. Be careful when hiring close friends.