first off all you create new document (file - new)
you must set paper size :
width : 800 pixel
height : 1024 pixel
after that make sure foreground and beground black color and use "paint bucket tool "to color paper
third step you change color foreground red, orange and yellow and using brush tool to create fire
four step using smudge tool to mix color
after mix :
add more color exampe blue color
after that smudge again
and approxiately like this and than finished
ok friend what do you think abot this fire, i think the fire is boxy, but this is just tutorial . if you wont to try it at home i think you could be nicer that my tutorial. thank for visit my blog see you next time :) bye bye.