So in terms of actual numbers you want to be playing around the top 20% of hands dealt to you in a 6 person poker game and the top 15% in a 9 person poker game. The number one reason why many amateurs lose at Texas Holdem is because they play way too many trashy hands! And that is, you need to play good poker hands in order to win.
My #1 Texas Holdem tip is one of the very first lessons in poker that any beginner needs to learn.