When training for the sport of soccer it is best if you take a multifaceted approach so you can utilize a variety of different skills.
The first major skill you are going to need for soccer is the ability to run both fast and for a distance. You are going to encounter both circumstances when you are out on the field, sprinting to get the ball and then also running with or after the ball for a field's length. Being strong in both areas is going to make you a much better soccer player.
This means that you should include both aerobic and anaerobic cardio sessions with your training. Aim to perform the aerobic ones for a period of about 30 minutes to an hour a couple of times a week. Then perform your anaerobic ones, preferably in the form of running sprint intervals another 1-2 times a week when you are feeling fresh and can give full effort. Note that this particular form of session is very intense so doing it before a game would not be a good idea because you would definitely be impairing performance.
The next skill you will want to develop is your coordination so that you can kick the ball into the goal. This is going to be best achieved through sport-specific practice. The more often you can get onto the field and practice shooting in different scenarios the more experience you will gain with it and the better off you will be. Remember as well that come game time you are going to have an increased amount of pressure on yourself and for many people this will affect their performance.
Learning some performance anxiety techniques would be very beneficial for you to help reduce the chance that you freeze up under pressure. Positive self-talk and imagery are both practices that most top-level athletes use both before and during their performances. They will help you to stay centered and focused on the task at hand.
Without a doubt the training you do for this sport is going to drastically affect how well of a player you are. Make sure you get a good personal trainer or coach to show you the best methods and then supplement those with proper nutrition and sleep.