Always trim off the excess burnt wood before relighting. Not trimming can cause the flame to be too high or even not stay lit. The pieces of the untrimmed wick can also fall off into the candle. Trim, trim, trim!
TRIM LOW
Trimming your wick to 1/8-1/4" will prevent the flame from becoming too large and ensure an even burn. Wick trimmers work great!
WHAT IF I DON'T TRIM?
Not trimming your wick can cause a large flame that could create smoke and even burn the candle too quickly. It is possible that the wick won't stay lit either.
LIGHTING YOUR WOOD WICK
Hold the candle at an angle when lighting; This is helpful if you are having issues with the wick catching fire. Make sure the flame isn't too high. If it burns more than an inch high, blow it out and trim the wick!