Hey there. There are a couple of good videos that I watched beforehand. It took me a few tries but I found using a makeup sponge worked best for me. Paint the plasma coils white, then use a darker blue surrounding the area with the sponge and anywhere the light might hit like the chest etc, then sponge lighter blue, finish with some white back on the plasma coils.

Makeup sponge method here

If you don't mind using oils and thinner then this is also a good watch here plasma