For me it’s an ongoing challenge to start a piece of music at the right tempo. Here are a few tricks I have used:
- Practice, a lot, with a metronome, to internalize and habituate the tempo.
- If circumstances allow, check a metronome backstage immediately before beginning the piece.
- If circumstances allow, have a metronome with you on stage. Most have a “silent” function that you can use to discreetly double-check.
- Maybe your piece has a fast or tricky part, and you’re worried that you will go too fast and that part won’t go well. Sing that part in your mind before you start to play, so you can pick a tempo that will work for that part.
- Be aware of your tendencies. For example, if the adrenaline of performance makes you tend to rush, you can adjust accordingly.
- Find a song that you know really well and have thoroughly internalized, that has a tempo very close to the one you wish to play at. Sing a few bars of the song mentally to find your tempo. For example, here’s a list of songs that have a tempo of about 94 beats per minute—I bet you can find at least a few that you know.