Keep your candles out of a draft. If the flame is flickering then your candle is in a draft and it will burn unevenly and/or drip.
Keep your wicks trimmed! Trim your wick each time you relight your candle. Use a wick trimmer or pinch the sooty end off before lighing.
How long should wicks be trimmed? 1/4" is a good starting point. The candle wick in a candle is constantly feeding fuel (the wax) to the flame and a pool of wax is created around it due to the heat. The size of this wax pool can vary due to wick size, ambient air temperature and humidity, thickness of candle, how long it has been burning and other variables. Observation and common sense are your best guides.
Candles need oxygen to burn properly. If the wick is too long or contaminated it will impede the flow of oxygen and cause your candle to smoke and burn poorly. Do not allow wick debris to collect in the wax pool.
Beeswax pillar candles benefit from a bit of love and attention. For best burning results, burn pillar candles until liquid pool of wax reaches 1/4 inch from edge of candle. Keep wick in center of candle. To prevent pillar candles from boring a hole down the center, burn candles for at least one hour for each inch in diameter (i.e., burn a 3 inch diameter candle for at least 3 hours). Keep an eye on your candle! If the wax threatens to melt through the side, extinguish the candle and let it harden before relighting.
The best way to extinguish a pillar candle or votive is by tipping the wick into the wax pool using a wick dipper or other non-flammable object, then straightening the wick to let it cool. This primes the wick for the next burning and eliminates smoking. For taper candles it is best to use a candle snuffer.
Never leave a burning candle unattended! Burn candles in proper holders and on a heat-resistant surface. Do not move or touch while hot or while wax is liquid. Trim wick to 1/4 inch before burning. Protect from drafts. Keep out of reach of children. Open flame - use caution and at your own risk.