In my experience, the only way to get better is to practice them. Just do drills with a partner, spend a few minutes working on different take downs, and then have your partner do the same thing. Then switch the style of take downs. Also, when you are going for a take down, don't aim to shoot at the guy you are taking down, aim to go right through him. By that I mean bust your hump and drive right through him and then turn or lift. Thats how I was always taught to do it and it worked pretty well. Good luck
I heartily accept the motto, "That government is best which governs least"; and I should like to see it acted up to more rapidly and systematically.