Always make sure wicks are 1/4 of an inch long before each burn. This will keep the flame from being too high or too low. Remove wick tops that look like "mushrooms".

Never leave a burning candle unattended. Keep lit candles away from children, pets, fans, air vents, and flammable materials.

There are many ways of extinguishing a candle. You can blow out the flame, use a candle snuffer, or just put the lid on. 

When burning a candle, allow the wax to melt all the way to the edge before extinguishing. This will prevent wax from building up on the sides. Never let a candle burn for more than 4 hours at a time. 

Always place candles on a level, non flammable surface such as a table or counter top. Additionally, a coaster or tray is a good option to protect those surfaces as well.

When your candle has about 1/2 inch of wax remaining, don't light it anymore. Doing so can cause a fire. Instead, clean out and recycle the jar.