In reguards to the balance problem. stand like a tori. now lean to one side till you naturally step out to catch your self. You can use this as a reference as to how far apart your legs should be. Another option is to extend one glute and more or less ignore the leg joints for a turn or two focusing on using your grip on your opponent to help you balance because team work is how you get things done in this game.
When taking steps if they are small ones you can try relaxing a knee as you take your step. this will help it not push you backwards off your toe. if its a large lunge type step contract your abs to help ensure your knee doesn't hit the ground either during the step if its coming from behind you or leaning on your knee after the step.
Do you know how to tripod?