Please trim wick to 1/4" before lighting for the first time.  On first light, leave your candle lit until the wax melts to meet the edge of the jar all the way around.  This will set the memory of the candle wax, and prevent tunneling.  

Trim your candle wick to 1/4" before each lighting.  This will keep the flame flickering just right, and prevent smoke or soot.