No worries...
you need an off camera flash lead to make it really easy...
a black background as far away as you can get it now infront of the black facing where the smoke will be aim it at the smoke plugged into the camera. then the smoke infront of it
and camera infront of that looking straight at the black...
light insence, and hold something where the smoke is rising to focus on.
get focused and take some snaps...
hopefully you should get a black background on some cool smoke showing in white...
I added the spoon for more effect...
then added an overlay of the rainbow colours...
and thats it...