i am almost finish playing my first play through as a ew user. I am planning on doing a second play through. I would like to be something like a shotgun/explsoive user. Is there any recommended builds i should use, or perks other then shotgun surgen?

If you have dead money then a perk is added calld "and stay away" giving your shotgun a chance to know people over.
Take all 3 ranks of demolition expert for 60% explosives damage, and splash damage for a bigger explosives radius. I would say better criticals because crits are always good. High luck to increase crits.