Go to the library and sign out some books on rhythm bands. Find out how they got started on their careers and the sorts of instruments they played.
Set up a timeline. A project like starting a rhythm band works best when there is a specific goal in mind. Pick a performance date or sign up to play in the local talent show to keep you on track with improving your musical skills.
Schedule frequent practice sessions. While people learning to play the piano can work on their own, being part of a beginning rhythm band requires everyone to get together for jam sessions. It is difficult to gain more musical experience playing the shakers by yourself.
Get a metronome. Try playing a piece slowly and as you get better at it, increase the speed. A metronome will help everyone in the band keep the same timing and rhythm.
Record your band playing. Listen to the band's performance and identify sections where you need to improve.
Learn to read music. There are only eight basic notes that you need to know, so being able to play them on a 12-note glockenspiel can be transferred to a larger instrument -- such as a piano or a guitar later -- when you get more experience as a musician.
Identity rhythm band role-models. Listen to the rhythm bands from West Africa and try to emulate their style. The "ngoma" music of East Africa is also infectious and makes you want to get up and dance.
Set challenges for your band as you gain experience. Rather than entering the local talent competition, for instance, make it your goal to win first prize.