Anybody have any pinewood derby car tips?

Hollow out big areas and fill them with weights. Sand it down as best you can to make it more aerodynamic. Make sure it's equally balanced.

careful about how much the car weighs because they will weigh it before a race, aerodynamics is key. Also veryimportant is wheels. dont pound to tight, dont leave to loose. if u bend the little nails get new ones cause a bent nail wont provide a good axel. Graphite on the wheels will help allot. Dont use liquid lubricants, like wd-40. they will pick up dust and hair and slow the car down.
Im helping my newphew with his.