Tips for playing without ego

While playing online, I find myself in tournaments and cash games alike always raising or calling when I shouldn't, because I get into hands and just can't let go of them. I get to where I think someone is always bluffing me or trying to steal my blinds. I try to outplay people too often and it is very very -EV.

I was just wondering what some of you do to check your ego at the door when you step in to a poker game.

Any help at all will be greatly appreciated.