First off, let me say this: I haven't been doing this as long as some others, but here is what my opinion is
The biggest thing is to have good flow (which is a given in any contest). My advice would be to work on your routine (get a solid structure) before trying to get fancy with whines and/or squeals. I like a good, powerful hail with a variation of ducks. I like to hear 3-5 really good hens along with a good cut feed. Try your best to not drag your hails out like a Mainstreet routine. As far as calls...blow what you have confidence in
Feel free to PM me if you need any help!