My husband done something years ago that i thought was ridiculous but it has work miracles with his knee strikes. He drilled a hole in a coin and tied fishing string around it. he had the coin stapled to the roof of our home gym. he would spend ages kneeing it and working on technique skills. then gradually the better he got, the higher it was put up. at first it was stationary but now it swirls around and forces him to strike it while it is moving. I never thought it would work but it certainly did.

He already had great power in his knee strikes but now he can get great height and incredible accuracy.

There's a reason you don't flying knee each other in training. If you have never seen one close up land flush you or miss completely and meet a counter its 8 of of 10 times one is attempted someone is getting hurt bad type move. I'd practice landing them from the clinch first then I would try for them in the open. The thing shaeek mentioned sounds like a good idea.

Basically practice jumping and lifting your knee at the same time as far as practice goes get one of your buddies to to hold there hand out while you try to break it with knee (that was a joke but that's how you want to practice)

I don’t practice it much, but when I do I grab the throwing dummy and stand it against the cage or the padded wall.

I want to get good at it. We don't do them at my mma gym and I think its a really cool move. Should I practice on a bag? Do shadowboxing? I have no clue how I would practice that. Also is there a specific combination that it would work well with? Help would be appreciated, I will take any advice.