I had an upper endoscopy (don't remember if that's the medical term) a few years ago after having this weird eating thing since I was little (that I won't go into details about b/c it's kinda gross - involves feeling like food is stuck and won't go down). They found all kinds of scarring and acid damage and evidence of past/healed ulcers, and I tested positive for H. pylori that another poster mentioned. Turns out GERD was causing my eating problems.
I got on antibiotics and prevacid, and it's much much better, and I don't even take the medicine anymore. However, the Dr. gave me a little booklet that pretty much said to avoid acidic fruits (citrus, tomatoes), high fat meals, onions, peppermint, caffeine, acidic drinks like coffee (maybe soda, too), alcohol, you know, all the good stuff.
But I've found that some of these things aggravate it more than others for me, and I think everyone is different so you may be able to experiment with what you can and can't eat. I've also read about elevating your bed and not lying down for a while after eating, but I've also read a lot of disagreement on that.
I hope this next part doesn't sound too alarmist, but, and I need to take my own advice on this much better, take it seriously 'cause if you have chronic GERD, sometimes repeated damage can end up resulting in stomach cancer.