Its a lot of running. Be prepared. Take a knee means get on one knee and not stand there like an idiot (learned from experience) make sure to change sides after half time (also learned that the hard way)
i would suggest you work on small touches like dribbling and juggling. then start working on accuracy for passing and shooting. ALSO MAKE SURE YOU WATCH PROFESSIONAL SOCCER!!! you will learn what to do in different situations by watching the best of the best.