1. Bill by the half-day, but don't charge for a 10 minute fix unless a client starts to get annoying.
2. In your first year aim for half of what you made the previous year. Take the best clients you can, but make sure you hit that or you'll stop. Don't take work that makes you feel icky.
3. Talk to people. Spend about 35% of your time doing it. Do work for free if you need to, but get someone talking one way or another or your pipeline will dry up.
4. By two years in you'll find a client that will make up over 50% of your billable. Do whatever it takes to make them happy. Even if you lose the client for reasons outside your control, make sure that the decision maker that brought you in feels like you did your best. They'll bring you in again, even if it isn't there.