Because wax has a memory, you should burn your candle such that the melted wax extends all the way to the edge of your container. That way, the next time you light your candle, it will remember to melt all the way to the sides. When you get a fresh candle, it may take its first few hours burning before it reaches this extended-melted state, so you want to make sure there's enough wax left over after the initial burn down to accommodate these first few hours. The longer you let your candle burn, the more fragrance it will release and the harder it will be to blow out. Most people don't realize how quickly a lit candle can burn down, so they're often surprised by how short some of the scents last. For this reason, it's best not to use all of your scenting agents on one go. It's better to burn half of your ingredient total than to run out of perfume entirely! Also, as the wick gets shorter, you need to trim it back so that it burns properly. If it starts to go out too soon, then more of the wax will be consumed instead of less and the flame will be smaller. This makes it burn slower and use more of the remaining scenting agents. Finally, when the wax is almost gone, you need to extend the life of the flame by blowing out the candle.