Why do some dancers excel faster than others? Maybe talent has something to do with it, but I believe that individual practice plays a larger role. You need time to focus in on the areas that are most difficult for you, to experiment with solutions, and solidify what you've learned. Class time is great for learning new steps, learning from peers, and gaining stamina, but it will never replace individual practice.
The most important thing is this: Don't practice what's easy. Engage in deliberate practice. Are en dehors pirouettes easy for you, while en dedans are more difficult? Then work on en dedans. Individual practice should be used to work through the areas that are most challenging for you.
When / where to practice
1. Practice daily, for at least 10 minutes. Set a timer for 10 minutes and work on things for that long. That could be releves, passe position, tendus, plies, etc. If you are practicing at home, I recommend slow movements holding onto a dresser, high table, or counter. If you live in an NYC apartment, you could try a few jumps but be sure to be mindful of your neighbors.
2. Incorporate practice whenever you can. Do releves while brushing your teeth. Stand in passe to wash the dishes. Practice how you should hold your hips and your core while waiting for the train to arrive.
3. If you can afford, book studio space somewhere like Ripley Grier. It's easy to book studio space and their facilities are equipped for dancing. If you can rent studio space, try to work by yourself for 1 hour every week or every other week, depending on your regular class schedule.
What to practice when you are in a studio
1. Warm up as you would before class. Start with a plie exercise as you would in class to warm up your hips and activate your core.
2. Write everything down when you are in class or taking a private lesson, and use what you wrote to practice individually. Perform some of the most difficult exercises and try to think of the corrections that you often get from teachers. Do they tell you to straighten your knees? Stop looking down? Keep your arm strong? Close your 5th? Tell those things to yourself as you dance.
3. Use music from Spotify or Youtube. There are lots of options for playlists for ballet exercises.
Whether you are at home or in a studio, use video your advantage. Record yourself doing a difficult step and watch it for feedback. Think of how it felt while doing it vs watching the video. "I felt like I was going to fall over in that pirouette, but now I can see that I was just fine until my knee bent". Think of what you would say to yourself to fix it, and try again with that in mind.