Try a friend's backyard, a local park, even a shopping center. Then you will have a chance to correct. Those can be hard to find, though. Often times problems in competition occur due to handling. But, sometimes the spirit of the competition and the excitement of it all just gets to the dog no matter what you do.
Experience seems to be the best cure.
If you can review a tape of your run, or have a friend watch it for you you'll probably get some feed back that will help you prepare for the next competition. Enthusiasm should be valued over all else. Keep it happy and keep it fun. It's much easier to gain control than it is to put enthusiasm back into the dog that has been screwed down too tight. This is just another training aid to add to your bag of tricks.