Burning your candle for longer than 4 hours can cause the wax to "mushroom" which leads to an uneven burn, and unsteady wick and a larger flame (more soot).
Keeping your candle capped while it is not burning protect the candle from gathering dust, pet dander or any other unwanted materials from getting into the candle which will later be burned... you do not want to be breathing that it!
Wind or drafts can cause uneven burns, which shortens the life of the candle. Wind and drafts can also affect the "throw" or scent of the candle.
Wicks should be trimmed as one sees fit. If you start to notice more soot than usual then be sure to trim that wick 1/4 inch from the wax line once your candle is cool.
Candles should be stored in a cool, dry place. Heat and humidity can affect the wax performance.
When you first light your candle make sure you keep it lit for about two hours or until the wax melts evenly across the surface of the candle. This prevents tunneling and ensures a longer candle life.
Do you know what's in your candle? I know what's not in a good karma candle! Unlike other mainstream candles Good Karma Candles are free of reproductive toxins, organ toxins, acute toxins, phthalates, mutagens, and carcinogens. Check out the "clean and safe scents" page for more details.