To improve with your balance, my suggestion may seem a bit unorthodox, but it has worked quite well for me. Ballet has worked really well for me in improving my balance. Since taking ballet classes, combined with tae kwon do classes, my balance has really escalated to an entierly new level. A technique that I have drawn from ballet can possibly be integrated into your training methods. The ballet position is called Arabesque. To start, move over so that you are close to a wall, and so that you are facing it, and within reaching distance of it. Now press your hand gently up against the wall and shift all of your weight onto the foot in which you are having trouble balancing on, or whichever side in which you want to work on your balance for this particular occasion. Lift your other leg up into the air, and point your back foot directly behind you. Slowly, begin to unfurl your backlack, pointing it directly behind you like an arrow. Once it's all the way behind you, start increasing it's level of elevation. Move it up higher and higher with gentle care. Sooner or later you will feel that higher up in the leg, the muscles will begin to feel very tight at the point where your flexibility ceases to be. Before you get to a level of elevation in which you feel as though your muscles are going to tear apart wildly, stop and let your leg rest in the air in that position. Now, while doing this, raise your chest up and out of your hips, and keep your chest up so that you aren't slouching with your leg pointed back. If you're extremely flexible, your body positiong will look similar to a "V" shape. It would look something like
this of course it all depends on how stretched out you are and how comfortable you are in that position. To switch the exercise up, move your head down towards the floor and while staying in this position try to touch your nose to the ground.
Another fairly simple way to improve your balance, is by improving your abdominal strength. Strong abdominal muscles allow the body to lift up out of the hip sockets and provide good support for the rest of the body's frame, which provides good balance. So anything that works the abs can be helpful.
Of course there are yet simpler exercises to improve balance, such as jump-roping, playing simple games like hop-skotch (primitive, but if employed enough and tweaked a little it can actually help you), and partaking in footwork drills. If you have a good jump front snap kick, you can practice doing one with one leg, and then landing with that leg down and the other up, and then doing it with the leg up, just switching from right snap kick to left to right in quick succession.
Well I'm done ranting and raving. Sorry about the excessive text I get carried away

lol. But I hope you can find something that I said at least a little bit helpful.