Bass jigs are worked slowly across the bottom, across structure and objects which might hold fish. Sometimes you might cast a jig into a good-looking location and let it settle a few moments before starting the retrieve. A bass will sometimes snatch up the bait where it lies.
But most bites occur when a jig is falling, either on the initial cast, or after a little jigging by the angler. A good way to imagine how to retrieve a bass jig is to imagine a cat responding to a ball of string being twitched across the floor. Work the jig slowly, with anticipation, as if bass were actually a cat hiding behind your living room couch, waiting to pounce on the bait.
Don't cast and retrieve jigs quickly, as with other baits. Each cast should take a little while. The strength of bass jigs is in their ability to be twitched and hopped along slowly, tempting a bass into taking the bait.
Bass jigs are great for going into heavy brush, and coming out with a fish attached. Don't be afraid to cast into fearsome-looking places with a bass jig, and retrieve the bait slowly, alert for strikes. Bass jigs are surprisingly snag-proof. If you do get into trouble, try jiggling the bait free instead of attempting to jerk it loose. It's uncommon to get snagged for good with a bass jig.