I have GERD and a probable hiatal hernia (too chicken to confirm that) I get reflux from air some days. :-)

Top on my list is caffeine. I cut WAY back on my coffee intake.
Some tips I was given are to wear clothes that aren't tight, sleep propped up at an angle, eat smaller meals, don't eat and immediately go to bed and take a tablespoon of apple cider vinegar when symptoms come on, though admittedly I just can't tolerate that last one.