Just keep your mind open, your smile wide and your dancing shoes polished. RSVP as soon as you get the invitation, either by phone or mail, if necessary. Or perhaps you're just required to buy your ticket. Prepare your clothes.
Some dances are formal, some are funky, but most are a nice mix.
Make certain your shoes are comfortable. If they're new, break them in before the dance. Make certain you have the right clothes and the right steps for the occasion. Be enthusiastic, especially if you're on a date. Save the first and last dance for your date if it's a formal occasion.