Three main things:
1. Buy a larger kettle, I have a 9.5 gallon which works for 5 gal. batches but if I could do it again I would go with a 12-15 gal pot.
2. More fuel efficient propane burner, the initial cost would already be made up in saved propane.
3. Don't drink while you brew, greatly assists in accurate measurements, hitting all your additions etc, have that homebrew when its chilling.