Here are some easy but essential tips to care for your candle:

First burn: Light your candle for 2 consecutive hours the first time. 

Every burn: Dont blow off your candle before the entire surface has melted. This will prevent tunneling and help your candle burn longer and healthier.
Trim your wick before every burn. If you don't have a wick trimmer, you can gently remove the condensation on the tip of your wick with your fingers. 
Never light your candle for more than 4 hours.
Keep your candle away from windows and air flows
Never leave a candle unattended