The most important thing is a race promotor that makes racers feel like he is there for the racers. Everything else falls into place after that.
I have been to quite a few races at various levels where the promotor seemed put out by the needs of the racers. These places will never host National level races again...and their club racing is hurting too.
The exact opposite is anything Scotty Ernst or Mike Boylan are involved with. They are class acts and they have extremely loyal racers that will come to their races as long as they have them.