I will go for lex , because he matched most of the things in a sig.
Vudzo had good idea , but you should worked more on smudge , spend more time on it and try :
-Using different brush patterns (download new brushes and change settings in window>brush , play with spreading etc )
-Use various brush sizes and also apply different hardness.
-Most important : Try to smudge out best colours from render and than use brush on layer above spray it with light colours and put them in different blending mode to make some lighting effects