The best advice I can ever give to anyone playing Earthbound for the first time is to find some way to get the official strategy guide. It's not terribly accurate and has more than a few glaring mistakes, but is by itself incredible. The writers went to incredible lengths to make a guide that followed the soul of the game they were writing it for. It is full of funny, off-beat newspaper clippings about the game, tons of custom artwork, and even has a couple scratch n' sniff cards at the end!
It's weird, and funny, and well worth anything you put into getting your hands on one if you're a big fan of the game.