Shoes are very important for a dancer.. You can either wear foot undies or ballet shoes these are Capezio two soles. Pointe shoes are also another obvious choice
Leotards are vital to serious dancers but amateurs can possibly get away with tanks. Black helps show your center and leotards help to see your rib placement
Tights are also a necessity. They show if your legs are locked and clean up your outfit
Booty shorts or spandex are optional over your leotards
If you have a more relaxed teacher you can wear tight tank tops.
Or possibly even compression like shirts..
Then of course hair in a bun. Preferably sock bun and bobby pins for fly aways.
Now you're ready for class(: