Using a double saucepan is not only the CLASSIC way to melt candle wax, but the safest method.
Begin either purchasing a good quality melt pot with a high mounted handle for ease of pouring and handling. You can also start collecting all sorts of tins and old pots that can be your wax pots. Of course for starters small tins are great, they only take 10 minutes to melt and you can make your first candle.
The pouring post containing the wax can sit in the water, or if you are only melting a small amount of wax for say a colour effect this can be melted in a small tin in the water to make a very convenient wax pot for small quantities. These tins of wax sit in larger saucepans or soup pots filled with water.
Have a thermometer checking the temperature, to keep it under 85 degrees Celsius.
Fill a box with pebbles and have it beside the melting pots; stand the moulds in this for pouring.
Have a bucket of water beside this area in case of splashes or leaks - the cool water will quickly seal any leaks.
When using glass containers, check for flame tolerance. Always burn candles on a plate with a heat pad underneath.
Never burn candles in a breeze or near flammable items (curtains); never leave burning candles unattended, or without responsible adult supervision.