The pentagram represents earth. Spells are usually done on a mat or cloth with a pentagram on it. The candle flame represents fire. Candle color is very important to most spells. Black and white candles are the most commonly needed in magick.
Incense represents air.
The incense scent may be important to the specific spell. Water represents water. The water should be in a special chalice or other container if specified by the spell. Other tools common in Witchcraft are altars, cauldrons, salt, and herbs or other botanicals, and incantations. Altars are said to be a personal working space and can be anywhere meaningful to the Witch.