Well it really depends on what you are looking to achieve. In general there are three styles of doing the sauce, or so they say. Of course there are thousands of other variations using fruits and other goodies....
The memphis (sweet), carolinian(vinagry), and the Texas (which is a combo of both).
I too have been experimenting with creating my own signature sauces--still have not found the right blend yet. What I did do is take three recipes, one for each category and start playing with them.
As previously mentioned sauce and rubs are the hard part of development.