Welcome to smogon! If you're going to build a team in the OU tier (or any tier) you might want to check the viability rankings first, they can give you some insight on what's being used and what threats to prepare for
http://www.smogon.com/forums/threads/usum-ou-ultra-viability-ranking-thread.3621329/
http://www.smogon.com/forums/threads/usum-ou-ultra-viability-ranking-thread.3621329/