This sounds like a no-brainer, but it isn't uncommon for women to shave before showing up for laser hair treatments, put makeup on before having facials or fiddle with their nails before visiting the nail salon. Nails can be persnickety, though. A good manicurist will know the right nail shape and length for you and have a better chance of getting your natural nails even. Your lopsided attempts to shape, buff or otherwise prep your nails in advance won't help the process much. Leave the work to the pros for the best results. They've seen it all before.