Single Candle

Candle magic is when you use specific colour candles in rituals or ceremonies to reach a special goal. Candle magic spells can vary from attracting love to removing negative energy from your environment.  
Most common in the Wiccan religion, casting spells using coloured candles is found it lots of other areas as well. 
Candle magic is white magic and is not to be used in an unsavoury manner, which is why in the Wiccan religion there Rede is "An harm to none do what thou wilt".  
Blue: A blue candle represents the element of water. It is used in spells to affect sleep or to awaken the psychic mind.