Some good advice I got: make sure that our partners feel that doing business with our company is predictable for them.
They know the way we treat them will remain consistent
The supports we give them is there and delivered
The quota we give them is not increased without solid reasoning
The overall discount we give to the channel is fair (so that everyone can make money and they know it, not just a few big ones)
The penalties shall be imposed as well. This is usually the tough thing to actually execute, but worth it.
For me, I extend it to the way I treat my partners. We recently had some discussion with almost no result with some partner, I felt tired but then still managed to walk them out of the building with some smile.
I believe, to show them that we respect them consistently even when they under-perform, also helps : )