1. Don't Play Every Hand / Do Fold More
Probably the number one mistake beginning poker players make is that they play far too many hands. When you're just starting out playing poker, you want to play poker, and that means staying in hands that aren't very good just to be part of the action. But playing more doesn't mean winning more, it usually means losing more. If you find you're staying in half or more the hands you're dealt, you need to upgrade your starting hand requirements.