Honesty, Honesty, Honesty, and communication. Be honest with the broker (regardless), be honest with the shipper, be honest with the receiver. One More honesty.....be honest with yourself. If any problem arises communicate with ALL parties making them aware of the problem and the solution.
Joining OOIDA, saying no to cheap freight and mean it, being on time with a safe and undamaged load (build that good reputation) and knowing what your true cost per mile is so you can control your expenditures (Good software goes a long way here) and knowing where to spend money and on what. I would rather spend money on the truck than paying the IRS. A good accountant that knows trucking will be able to let you know where you are at but it will cost you. The acct. is a write off. and the only other thing I can say is plan ahead and always keep a backup plan for when poop hits the fan. Keep a positive attitude