I am patient and flexible and I tend to form lasting relationships with capable providers, using their services over and over again.
When dealing with new providers I use GAF's escrow option exclusively. When dealing with established providers I generally use bank wire, depending on the providers wishes, but other payment methods are of course an option.
When I post projects I try to describe the work briefly but in sufficient detail so that providers can accurately estimate the time involved and the cost of the work. If clarification is needed I'm always open to discuss them.