my tip.
make sure youve got plenty of money to live off while you build up a customer base, about 2 years worth should do it.
tip 2, do the best job possible even if it takes you twice as long as you first thought it would.
what should you charge, how longs a piece of string.

if your setting up a business then you should know how much you need to charge with your business plan. if you haven't got a business plan, your beeeeeeeeeeped.
derek