My senseis have told me that I lack balance while demonstrating kicking techniques and Katas. I'm looking for advice on how to train to improve my balance, for example are there any good drills I can do? Should I simply practice kicking more?
Improve your leg Strength.
Do this first because it feeds into any activity requiring balance.
Make sure you don't stand up all at once from stance training and don't overdo it. Your legs will shake. This is normal. If you start to go all wobbly, though, time to give it up for the time being. Come to a neutral, bent-kneed posture and stand up from there whenever you are coming up from your stance training
Improve Core Strength
Your core goes into stabilizing your body during single-leg techniques such as kicks. Tons of sit-ups are not necessary and may even be detrimental if you train them wrong and strain your back.
Just do it!
Supplemental strength training as outlined above is important and will help you stabilize your body, which is really what balance is. But a lot of your improvement is going to come from repetition of the activity that you require balance for. After all, what better way to train balance for kicking than to kick? An individual kick technique requires certain muscles to activate and the body to stabilize itself in a certain way that only that particular kick can truly replicate. So, if you're falling over when kicking, what you need to do is kick more!
Try kicking as slow as you can.
For example, a front kick:
Good Luck in your training.
zhan zhuang or stand like a post. (the article is rather terse, but the references at the bottom will probably be helpful. I'm not sure this is a skill I'd want to learn from the internet, but any practitioner of Chinese martial arts should be able to help you with the basics.
You need to improve your stabilizers - the muscles that surround your ankles and enable you to balance. standing on one leg for extended periods of time will improve these muscles. Start by standing on one leg for one breath, then switch to the other leg. Then shoot for two breaths. I'm not saying that "breath" is a magical period of time, I just find it convenient. I can practice while waiting at the bus stop without any equipment at all.
Mentally, take a step back and think about what your performance of these techniques is like. If "poor balance" were specific to a kick or two I'd be worried about flexibility, but if it's pervasive through kata then it sounds like your mental focus and attitude to the technique is wrong. Think more about clean, minimal, precise movement, with the body rotating cleanly and crisply around your centre, and less about eeking out the last 1% of reach or power that you might think's available from a larger, less controlled motion (which may well be reducing your power anyway ;-P), or visualising opponents, or speed, or whatever else is driving your current performance. Visualise each movement being done cleanly and with good balance - watch someone whose performance you aspire to and pay attention to their overall bearing - and then hold yourself to that as you move. Be aware of the position of your head and arms, the angles of feet and hips at which the movement should stop to retain balance, and the speed of your recovery from techniques.
When practicing kicks, it's good to drill kicking in the air at full speed and stopping with the leg extended, as well as kicking and returning the kick to the starting position on the floor with no net change to your stance. If you find that difficult, reduce speed and pay very close attention to what part of the kick you're losing control in - experiment and reason about your technique, and watch how others do it - until it improves. Ask for help with specifics if you're stuck.
A simple practical exercise that will improve your kicking balance: Do straight leg kicks without ever setting the kicking leg down.
You don't have to do them aggressively or high at first. Even a 30 or 45 degree kick is sufficient to start you off. But when the leg returns, either don't set it down, or do the lightest toe-touch possible.
Gentle, controlled straight leg kicks that do not end with your weight rebalancing over two legs train you to keep your mass over your supporting leg as you kick, and help you gain the proprioception (sense of body position) necessary to remain balanced. This practice may be frustrating at first, but it will greatly improve your kicking balance. Because it avoids shifting your mass as you settle after the kick, it will also improve your kicking speed and rate (how many kicks you can do per minute).
Once you've got straight leg kick working, you can move the same skill into more difficult motions such as snap kicks, side kicks, etc.
Slow kicks and slow leg raises. Balance is a feedback game - your proprioception and your muscle response. How fast you can sense your own balance, and how fast you can get your stabilizers to do the necessary micro adjustments in firing the correct muscles.
When you balance or stabilize, it's not like your body turns on ALL of the stabilizers at once - it turns on just enough to keep you upright. So slow movements wear out the set that your body first goes to, then forces you to use different ones, training those, as well. This is why dancers, acrobats, and experienced yoga practitioners have very good balance- they're doing extended holds and slow movements.
When you feel good with that, you can move up to giving yourself smaller or less stable platforms on which to stand. I've seen folks use a brick as a smaller thing upon which to stand, standing on the edge of a phonebook, or something slightly wobbly, like a cushion. If you're feeling really advanced you can go up to a wobbleboard, but you need to be careful so you don't give yourself an ankle sprain or knee injury when you take a fall from it.