Heat, oxygen, and fuel. Water is a material that can't catch on fire. Water smothers fires by depriving the flame of oxygen. For oil fires, extinguishing materials such as carbon dioxide foam, sand, and even baking soda can be used. A flame is the light given off by the sooty fuel reacting with oxygen.
Flames produce different colors depending on what's being burnt.
If copper is being burnt, it will produce a green flame. Wax is the fuel of the candle. A flame consists of hot particles and gasses. Hot things rise, therefore the flame stands upright.