It's as easy as 1, 2, 3...
1. Trim your wick
Trim your candle's wick to about 1/4" before each + every lighting. Do not allow your wick to curl over, as this can create a larger than normal flame.
2. Let it burn
Allow the wax pool to melt to the edges of the jar during each burn to prevent tunneling.
3. Be safe!
Do not burn your candle for more than 4 hours at a time and never leave a candle unattended.