Team Comps

I play on a team with five other people, and while we're decent we just play whatever we feel like and don't really think about team comp. I'm looking for some suggestions on team comps. These are what we main/can play well - do they work well together? And if not what should we change? Top: Main = Darius, Other = Nunu Mid: Main = Anivia, Other = pretty much anything Jungle: Main = Master Yi, Other = Kindred, Amumu Adc: Main = Corki, Other = wants to learn Tristana Support: Main = Soraka Other = Janna, Sona

Thanks!