Trim your wick to about 1/4" before each burn. To extend the life of your candle extinguish the flame after 4 hours and trim the wick. This will ensure a long lasting candle, minimize soot and remove any mushrooming of carbon on the end of the wick.
Extinguish your candle by placing a lid on the candle or dipping the wick into the melted wax and straighten. This will stop the wick from smoking and will help with re-lighting.
Extreme temperature fluctuations can cause sweating. This is normal, wipe off the excess moisture, or burn you candle.
On the first burn allow the wax to melt all the way to the sides of the container. This should take 1-3 hours. Failure to do this will often cause tunneling which can limit the life of your candle.
If tunneling occurs set your oven to 175°F, and place candle in for about 5 minutes to allow the wax to level out. Remove any excess wax if needed.