First tip: No dishwasher!! That will ruin it faster then anything else.
Second tip: get some furniture stripper from a hardware store, and while you're there, pick up some #000 steel wool and some tung oil. Remove all of the ironwear before you start working on it.
Third tip: Once you have it cleaned down to bare wood, put on a coat of tung oil. This might take up to three applications over several days, with a wipe-down with more steel wool every day.
Finally, polish it up with some hard paste wax.
It will be like brand new. Trust me, I've done this before. It works.