Simplicity is the key especially when composing vg music. One of the best examples of simplicity would be Pokemon Red, blue composed by Junichi Masuda. He really doesn't have may parts in each track, but the way they play off of each other (a lot of times with a call and response pattern) it truly helps to make a timeless theme.
Although things have gotten more involved, the tracks that always shine through are the ones that keep the overall composition simple. So go and study some music and composers. Looks at the patterns in their music and see how they use them. Breakdown some of your favorite songs and see what kind of patterns cord progressions and rhythms work for you. It will help you to discover your style and help you to move beyond just duplication.
Hope that helps.