To get the most from your candles here are a couple tips and tricks you can use.
1) Trim your wick. - Before you light your candle make sure there is around 1/4" of the wick above the wax. Long wicks can create soot/smoke coming off the candle as well as overheating the container.
2) Keep the wax clean - If foreign debris gets into the wax it can cause it to burn unevenly which can lead to wax tunneling.
3) Burn the candle until the wax is evenly melted across the top of the candle - Let your candle burn until there is a layer of liquid wax across the entire top of the candle. For estimated times - refer to the product page
4) Burn your candle on an even and level surface. If the candle is tilted in a direction the wax will unevenly melt which can lead to the container overheating and/or wax tunneling.
5) Reduce drafts - Drafts can create smoke/soot coming off the candle, uneven wax melting, and overheating of the candle vessel
6) Keep clear of flammable materials - Use common sense in your candle placement, please don't put the candles in a location that can create a fire
7) Stop using the candle once the wax is down to 1/2" from the bottom of the candle - Burning the candle beyond this point can overheat the candle vessel and lead to additional damage