Well i find that to make sword and power swords differently is to paint the electrical effect in my opinion, some people just paint the metallic, some people add effects with wire and green stuff, but if that's not your route there are many ways. People use the technique that i do, blend, and do it so many different colors, almost any you can think of you can do.
Heres an example of a power sword i did for this
WIP storm trooper sergeant i did
Did it with ice blue, washed with asurmen blue, went over the areas that i wanted white with the ice blue again, then did watered down layers of white until im satisfied with the result, and you can change that order to any color with the corresponding wash, just build up the colors to white and your good!
Everyones power weapon turns out different and all depends on preference, it all depends on the amount of effort you want to put in and the effect your going for, i go for a distinct weapon that isnt to flashy yet looks good in my opinion, hope that helps!