My suggestion is that everyone keep a simple dance bag because its a lot easier to find stuff if your in a hurry. Trust me I had the messiest bag around and then I cleaned it out and found about a billion class schedules I needed that I couldn't find, becuase they were buried at the bottom.
2. Hard shoes
3. Towel-because we all sweat
4. Water Bottle- I usually have 2 big ones
5. Pen and Paper or notebook. To write down new steps
6. Dance Sneakers- they are absolutly amazing for practicing hardshoe and softshoe without wearing them out.
7. Practice poodle socks. I always have an extra worn out pair so I don't ruin my good socks.
8. Extra shoe laces. There will be a time when one breaks, so you'll want to be prepared.