I think there are 3 main components to balancing.
1. The sensitivity/ function of your inner ear etc
Can't do much about this (unless there is a medical issue that can be fixed) so just work with what you have..
2. The ability to actually read the signs that you are off balance.
I think this just comes with practice time. You slowly get more sensitive to recognizing the signs of the bike falling earlier and earlier and the corrections get smaller and smaller.
3. The actual techniques used to correct the balance.
I started first with the bars to one side and practiced correcting the balance with small twists of the bars left and right. Once I had that working OK I started to try with the bars centered. Try putting a beer crate on the left to rest your foot on then slowly lift the foot off the crate but don't be in a rush to bring it to the peg. I found I would naturally bring the foot closer or further from the bike to maintain balance.
Once you get the left foot to the peg you will probably find the bike starts falling to the left and it's time to swing the right foot out. You'll probably over compensate and then need to bring the right foot back in and the left out again.
After a few months of practicing a few minutes every day, I found that I was only swinging each foot out about 6 inches or less and placing it back very gently. The corrections have become so small that I can often just move my hips from side to side now.
One thing I have noticed with balance is that initially the exact point of balance feels really weird/floaty. Suddenly there is no feedback to tell you which way to react. You get so used to fighting one way then the other. When you actually balance, you need to stop reacting and wait briefly for the feedback to tell you what to do. It's this feeling you need to get used to.
Anyway bla bla the main thing is regular practice and I still need a lot more..