And we often say "keep in practice" or "stay in practice."
Usually, you keep in practice if you already know how to do whatever you're practicing: "She sounds great on trombone because she keeps in practice."
If you keep practicing, you might be experienced or you might be a beginner. It depends on the context.
- Beginner: "I'll keep practicing until I can do it right every time."
- Expert: "It's a beautiful day, but I think I'll stay home and keep practicing."