Serious advice, but use it at your own risk:
1. Parking garages, preferably the tallest one you can find. Please do so only when car traffic is minimal.
2. Train tracks, stepping only on ties (not on the rock area). Again, please do not be stupid and try to take on any trains.
These two really helped me - yes, I am being serious.
Third option, if you can find a tall enough building: stairs. When you have mastered coming down them, start taking them two at a time. Much harder than you think.