How to Add Realistic Fire

You will have to create a new layer, and already have the fire brush loaded into you presets. After that, you will use layer, layer styles, then add an outer glow with red at hard light at size 10, then add inner glow with an orange size 5 and hard light. Duplicate the layer, then use fire brush on that layer. It will use your adjustments on this layer and create realistic fire.

https://www.youtube.com/watch?v=-x2ilR6XpaI