Use good old charcoal and wood chips.
Despite the convenience and control that comes from using a gas grill, you'll get richer, smokier flavors using charcoal and wood chips. The idea is to soak the wood chips and then place them directly on the fire after your protein has cooked a while and is just two to three minutes from being finished. (For gas grills, use a smoker box or wrap a pile of damp chips in aluminum foil instead.) But there's no need to stop with smoke. "You can influence other tastes by using fresh herbs," says Chef Burke. "Add fresh rosemary to the coals for the last two minutes of cooking pork, or try cinnamon when grilling chicken."