Learn how to defend. Defending the goal is an underrated achievement. It can be extremely difficult staying on your man or getting the ball away from your man. There are three basic things that you need to remember when guarding a player in soccer:
Don't be fooled by feints, tricks, or jukes: keep your eye on the ball. A good soccer player will try to juke or feint with their body in order to get past you. They're hoping that what they do with their body will distract you from what they're going to do with the ball. Don't let this happen. Keep your eyes on the ball at all times, not on the player.
Stay in between the ball and the goal. In other words, don't let the ball get behind you. This is harder than it sounds. It's a delicate balance keeping enough pressure on the ball and giving the person who's attacking enough space so that they don't get behind you.
Learn to anticipate the dribble. Right after an attacker hits the ball on the dribble — that's the time when try to hit the ball away. This is called anticipating the dribble, and it's essential for knocking the ball from an attacking player. Just be sure not to lunge and miss; you're vulnerable when you do this!