>>19836419I can't recommend sweepercalc enough. Bookmark it, open it in a tab, and use it. You can get a feel on the common trends by looking at their usage statistics, and you can use their break/wall my team feature to see the holes in your team.
Also use
http://pokemonshowdown.com/damagecalc/. It might seem like cheating at first, but you're just testing things to learn what to expect, which is something that expreienced players will already know. Maybe that guy who has played for years knows how much banded Staraptor's Double-Edge does to a Terrakion, but you don't, so you should find out without risking a game.
Also, get out of OU as soon as possible. It will break you unless you're resigned to possibly not using your favorite Pokemon. If you love Feraligatr and want to use it, check out NU. Like Infernape? He's UU along with a lot of other likable and fun mons, so try that out. New players might get put off by how few Pokemon seem to be used in OU and get put off when in reality there's quite a bit of diversity. So find a lower tier you like and stick with it, moving to others when you want to see what their metagames are like. Unless of course you're playing on cart, which to that I say dump it and play on showdown since you won't run into dipshits running Mega Kang and Darkrai when you're trying to play with OU/UU mons.