Learn to sing or play an instrument. Better yet, learn to do both. Most cantina bands feature instruments such as guitars, drums, keyboards and basses.
Research an existing band if you are going to audition. Listen to a few of their performances and find out what type of music they play. This will help you to decide if you will fit in with the group. Some cantina bands play more rock-and-roll, whereas others may specialize in country music.
Learn crowd-pleasing music. Most people go to bars to relax, unwind and have a good time. Upbeat songs, as well as a few humorous songs, are generally well-received.
Expect to adjust your schedule. If you play in a cantina band, chances are you will have late nights. This means that you also may need to sleep in a while to recuperate.
Dress in a style that fits the particular cantina in which you play. Each cantina has its own vibe. The essence of most cantinas is a relaxed atmosphere. Some cantina bars may have patrons who mostly wear jeans and boots, whereas others might have an island-beach sort of feel.