Jun, Here's a far easier way than any of the above - find someone who knows tae kwon do, and have them teach you the first kata called "chon ji." That'll do more for you than trying to focus on 17 things at once.
Our sensei also teaches tae kwon do and Okinawan te, and to help us use more effective kicking and striking attacks, he taught us these from that background. I got interested and learned some katas, and they did an incredible amount to improve my balance in the early years. In the kata I mentioned, the movements are very simple, but if you try to finish each move in balance it will impact your aikido very, very positively.
Another tip, if you're finishing off-balance and finding yourself falling forward or on top of uke, it may mean you need to take a step in that direction. Some readers here may not like that answer, but precision is in results not necessarily in rote execution of techniques. O-sensei taught principles not techniques, the techniques were just expressions of what he was teaching. Students say they frequently changed from day to day, so I take that as a guide that matching the situation at hand is more important than matching someone's technical manual.) Good luck!