1. Light your candle in a well-ventilated room, away from drafts, or fans, which can cause sooting (black marks on the vessel), or rapid, uneven burning.
2. Burn regular-sized candles for one and a half to two hours at a time. Burning for less time can cause the candle to 'tunnel', which leaves a build-up of wax around the vessel's sides. Burning for longer periods (over four hours) can cause the wick to move, or slant.
3. Make sure you stop burning your candle when 10mm of wax remains at the bottom, keeping an eye on a burning candle when the wax is low.