I can tell you what works for me .
Start with
S- 5
P- 6
E- 5
C- 4
I - 7
A- 7
L- 6
I usually tag energy weapons (obviously) repair and speech. Though science also useful to EW users
Beyond that, if you like sniping and use the YCS-186 or Gauss rifle, then definitely chose meltdown as a perk along with finesse and better criticals . If you prefer medium to short range like plasma rifles and gating lasers , chose the laser commander and plasma spaz perks.
*Edit
Flamers and incinerators also count as energy weapons..
Overcharges work well on armored targets.
Keep an eye out for dead Bright Brotherhood members as they will often have valuable EWs on their corpses and can be found early, like in the coyote cave just south of Goodsprings and under the bridge on the road south of Sloan . Finding a plasma defender early is very helpful to a low level EW character.