I AGREE with all these people!!
the BANDS are definitly a good idea, rolling the ankles and pressing through will help strengthen your feet
the ledge is also very helpful, but..be careful because DROPPING down too fast will result in some very painful achillies tendon strain
one thing to strengthen BOTH your legs and ankles is to lie down on your stomach, folding your arms underneath your head, fold your toes to the ball of your foot and straighten your knees hold for 8 counts rest for 4 counts and then just slowly build onto that, but be sure to STRETCH both before and after doing this as with any other exercise, especially this one.
one foot eleves and releves will always help, and one exercise also be very light with this as it too has its dangers, is to rise up into a RELEVE and stretch one foot at a time to your point but be careful and DO NOT put any weight on your toes just feel the roll through and the effect of the work but BE CAREFUL!