Good players win most BGs, people asking this kind of stuff are usually the people who AFK at base and give good players a hard time carrying a 90k hp rogue stealthed on base. If you make a decent 5 man premade you'll win 99.5% BGs you play.
If you are trying to gear up your chars in bg's you will not have a good time.
Always when playing against Horde, there's that pesky hunter or a disc priest.
Always when playing agains Alliance, there's that stupid donor rogue/mage/shaman which doesn't have any fkin arena rating but he's good at bragging about his KB scores in Goldshire.


All in all skill matters but no gear means you get pwned. But stay persistent you'll gear up eventually.