The key to making a gas grill have better flavor is to line up grilling rocks under the grill/grate. When the food drippings start to collect, every time you turn the grill on it smells as if food is already on it. It seasons it. I've had the same rocks for 4 years. When the grill gets hot your mouth will start watering.
reminds me of the old married with children episode where Al's grandmas ashes were in the grill...er somthin like that
get charcol...heat em up and use hickory, mesquite or apple chips depending on vittles, pre soaked in Jack Dans with honey...soak the chips for about 4 days in the fridge..bag enough of em per serving then stick in the freezer...when its time..toss em on the hot coals..removed from the bag of course...works great with fish and apple chips