surfing crappy waves seems to help my surfing
and half pipes with regular skateboards
longboard skateboards will help with longboard surfing, not very explosive though
If you dont use a skateboard try finding a hill where you can run up and down it like its a wave. practice using your arms to motivate turns while running up and down and lengthwise to the hill. Its a different way to use the landscape but it really works..not to mention great cardio while your out of the water. the land along on and off ramps are a good example. Also sand dunes.