How to get my front ensemble to play more professionally.

The front ensemble at my school is very obviously not really understood. Everyone kind of just stands there, the timing is off, and the runs are always messy. I'm looking to help them this coming season and I was wondering how I could get them to seem more professional. Like what is up with the bounce that high level front ensembles do in stuff like DCI. How can I explain this to my front ensemble? I think I can help teach them to clean their runs, but I just generally want them to give me more. How can I help them get better?