We have a somewhat slating style.
We all openly say what position we would like to have, primarily and secondary (if there is a second choice).
In our experience, if people get what they want, they will be more enthusiastic about doing that position. They want it for a reason, maybe they have great ideas. Maybe they are taking the job with the least work involved, because they don't want to work very much. Are you going to tell him/her that they have to take one with more work, and risk having no work done for that position?

So, if someone is uncontested in a position, they automatically get it, basically.
We have strict requirements of who can run which position however.

Finance needs to have a university math course under his belt.
President, Secretary, Finance and Vice President all need to have a course in Human Resources.
And etc.
Plus, some usual (not always usual), President and Vice President cannot be freshmen, or sophomore, must be at least Juniors. Same with Recruitment Chair.

Etc etc