I'm with the other Rob. Walking is good.
There are some other rules that help too:
1. Never park next to a 2 door car, particularly if it is uphill.
2. If given a choice of spots, pick the one that is on the end and on the passenger side of any other cars. Statistics help here since most cars have only driver.
3. Locate the MINI parking spots in your usual destinations. I've found several in my normal travels that only fit a MINI or very short car. A bonus is that these are usually on the end of the row and you can park straight in rather than diagonal like everyone else.
4. If you must park amongst other cars, find the guys who are using the same strategy as you to avoid door dings and park between 2 nice cars, particularly if they have been tricked. This is a trust your buddy thing but your odds are much better than other spots. Kind of a mutual protection thing.
5. If you must go to places that really have lousy parking lots (Best Buy in Lynnwood for example where the parking is packed and spaces very small) take the other car. Leave the MINI to roll another day.
6. If you park in a lot with assigned spots, meet you neighbors. Show them your cool car and how proud you are that there are no dings. If you are going to keep it that way, you will certainly need their cooperation.
My $.02