Power points, power points, then more power points. Mine is 6 x 7M and I have 20 x 10 amp, 1 x 15A and 1 x 32A power point, it's not enough! I also recommend insulating ( I went with noise insulation bats) and lining, 12mm ply is great, if you want something on the wall, screw it on, job done!
I also installed a cabinet with extra noise insulation for my air compressor and ran hard air lines around 3 walls with 3 outlets on each wall.
I also went with 3M hip height, and installed a beam across with a girder trolley and chain hoist, the extra height is great for storage as well, but if it's not in the budget, it's not in the budget.
I painted my floor with a Resene non slip 2 pack epoxy paint, makes it very easy to clean up spills etc, well worth the money.
It goes without saying that good lighting is vital.