Firstly, Arc Lightning is your friend, and everything single-target is all about Arc Lightning. It's probably second only to two-gun as an ST maintain by itself, but you can make it do far more damage. Ball Lightning and it's advantage can guarantee negative ions, to boost arc lightnings damage further. After that, it's all down to energy unlock. You want either overdrive or ionic reverberation. Ionic can provide so much energy that with arc lightning that if you have a high intelligence and endurance, you can literally and indefinitely maintain it.
Many of my toons use electrical due to how effective it is. Ego/int/end can be a good pure damage, con/end/int is another good combination. If you go for overdrive you can swap end out for recovery, as overdrive actually benefits quite a bit from recovery. But you should always do something to get negative ions on enemies so you can maximize arch lightning damage.
For AoE damage Gigabolt has always been a very heavy hitting attack, and is actually a very good yet practical force cascade. Lightning storm is perhaps the more damaging per energy and easier to use, but both benefit from ionic reverberation. As for passives, I actually always use night warrior if I go for a damage build, but thats cause it helps all forms of damage(and ignores some enemy resistance) and has some dodge/avoidance. But then I rarely go for pure offense and usually just go for regeneration anymore due to the safety of underestimation from shfg's/scrubs.
