Team Fortress 2

I am a new player to team fortress so can anyone help me out learn the game I've put like 12 hours on the game and I still suck unless I am using the engineer.

I played about 255 hours, its not a lot compared to really good players, but if you need someone to give you a hand with the game, I don't mind helping and playing it some more, we were all beginners at some point plus I just love the game haha. I'm a pretty good soldier and sniper, a decent scout and heavy, but all else I'm not too good at.