Take a favorite cartoon or anime like show, take some clips, mash them together and add music to it. Try to pick out a specific theme in your clips that follow the theme of the music. Keep an eye out for changes in the music and plan your clips accordingly.
The cartoon I chose was Pokemon. Growing up as a 90′s kid pokemon was extremly popular back in the good days and it still is today. It also shows how powerful friendship can be so this also relates to it