I found it very helpful over the holidays to practice with a video camera recording my progress. I played for 5 minutes, and watched 5 minutes. The camera was positioned so that the keyboard of the xylophone was visible. I was able to see and hear what was working and what was not and adjust accordingly on the next round of playing.
If I can help you, call me.
The above is the final take in ten takes over 20 minutes.
You've got to learn your instrument. Then, you practice, practice, practice. And then, when you finally get up there on the bandstand, forget all that and just wail.
I'm a professional pianist and music educator in West Toronto Ontario. I'm also a devoted percussionist and drum teacher.