Kikkoman's Teriyaki marinade works really well. You can buy a jug of it at Sam's.
That, salt, and brown sugar sprinkled on the meat before drying is quite good. A couple ounces of bourbon in the marinade is good too, along with a tablespoon of Liquid Smoke.
I love garlic but for some reason it doesn't set well with jerky, so I leave it out.