How do you fix years of improper shaving?

Ever since a few years ago I have shaved improperly because I always get ingrown hairs or get razor burn. Is this because I shave the wrong direction? Which way is the way your suppose to shave your facial hair? I heard shaving against the grain is a no..but what does that necessarily mean? Also since I have shaved inproperly sections of facial hair are growing in different directions...how do I take care of this? everytime I shave with the grain..the hair never seems to shave off my blade slides right over?? whats with that?