To answer that first question, yes!
It is very important to trim your candle wicks in-between burns. Candle wicks should be trimmed to approximately 1/4" prior to each burn. Doing this allows your candle to have a clean, even burn each time and increases your candles burn time. This means more value for you! You can use a pair of regular scissors or a wick trimmer.
Burn your candle long enough to avoid "tunneling"
Each time you light your candle, ensure you let it burn until the wax pool reaches the edge of the container. This usually takes about...