When you have a goal of improving a specific movements, it's easy to think the best way to do that is to practice that movement over and over again.
News flash: There's a more effective way of improving something like a pull-up or a muscle-up than sticking around for 20 minutes after class and logging repetitions.
My goal since I started training almost 9 years ago was to get better at muscle-ups—a persistent weakness for me. A recent foot injury allowed me to spend a ton of time developing my pulling strength. I can say with confidence that is IS WORKING! Finally!
Yes, I have been practicing muscle-ups twice or sometimes three days a week, but what has helped even more than that has been the variety of pulling accessory work I have been doing. Seems strange that a bentover row or banded lat pulldowns might translate into better muscle-ups, but the variety of pulling I have been doing has been making all the difference—pulling from different angles, pulling at a variety of tempos etc.. Not only that, but variety has allowed me to do more volume and ultimately improve my pulling muscular endurance, as well.
If you have a specific goal you want to achieve—be it a better clean or better pull-ups—talk to your coach about putting together a systematic plan to help you get there in the most effective way possible.
I'll leave you with this: These drills have made a huge difference to my ring and bar muscle-ups in the last 3 months. Some of them you may recognize...others not do much...