When lighting for the first time, let the wax melt completely to the sides to prevent tunneling (around 2-4 hours for out 8oz candles).
Trim your wick to 1/4in each time you light the candle. This helps the candle last longer and prevent extra soot. Remove any "mushrooming" that occurs at the tip of the wick.
Dip the wick in the melted wax pool to extinguish the flame. This prevents it from smoking after being blown out.
After the candle has cooled, replace the lid to prevent dust buildup in between uses.