Best tip I ever got for shaving is to use a crystal salt stone after the shave. I went to an old school barber to have a shave many years ago for fun and this is what he used. I've been doing it ever since. I highly recommend it, it totally prevents any rash or reaction you might get after you shave. There's no need to use anything else (aftershave, lotions, etc.)
After you shave, spash your face with cold water and then rub the stone all over your face and neck, then splash with cold water again and towel dry. Try it, you'll never go back.
Something like this:
amazon.com link »