Make sure your're confident and can be loud. Also, check with your director on how to conduct, you want to make sure you know how. And don't be afraid to move a little when conducting, it's okay to get into the music. Make sure your band trusts you, a good relationship with them is the best thing you can have.
Some characteristics include being more artificial, with exaggerated proportions, and distorted perspectives. Mannerism took influences from the high renaissance period.