Little help/tips

[OneKiwi]

Right I have this shell that I am going to do another for a club mate.
Sorry for the bad pic



THe yellow at the front is going to be a fluro on the next shell.

My question is how can I shade the flames so they come out better and a little more contrast between the yellow and orange an not use a separating line?

Do I have a little darker yellow around the edges?
Go a lighter from nose to flame end on all colours?

Thanks for any input and tips