If you’re a Trapsin relying on lightning damage then you’re going to struggle with a lot of Hell encounters. I can only tell you what I do with my build. I’m not some super leet, awesome player with Godly skills and gear, so some other forum users who are really, really good at this game might have other ideas, but it’s what I do - and it’s got me to L100 on at least two occasions over the years on different Assassins I play, and to L82 on Hardcore.
My build relies upon Death Sentry rather than Lightning Sentry as the corpse explosion doesn’t care about elemental immunities and is capable of clearing entire rooms very quickly.
I like to have Crushing Blow and open wounds, and the easiest way to get this is the Duress runeword on your armor. Open Wounds will damage physically immune monsters as long as they also get damaged in some other way, so I’m also stacking poison with maxed-out Venom and cold damage which is intrinsic to Duress, and also on my weapon.
Maxed-out Shadow Master is very, very important to tank packs of mobs and keep them occupied and away from you. I personally prefer to use Shadow Master rather than a Merc to tank for me, as she can be instantly re-summoned if she goes down (which usually only happens with bosses and cursed elites). I used a ranged Merc from Act 1, and again I like to stack cold damage on her.
Fade keeps mobs away from me, and focussing on Shadow Master.
For my main attack I use Blade Fury and fight from a distance. This is a one-point wonder that relies upon weapon damage for it’s hitting power, so it will always be as powerful as the weapon you have equipped, there’s rarely a need to put any more than one point into it. It works with any melee weapon type, and I like to use a one-hander plus a shield to help boost my resistances, but some players prefer to sacrifice the defence and use a two-hander for the extra damage.
So a typical fight inside Maggot Central would go something like:
Open door / get Shadow Master inside to start tanking / put down plenty of Death Sentries, pew pew from a safe distance outside the door. As soon as those pesky beetles start to go down Death Sentry sets off a chain reaction that causes massive explosions, usually killing off the entire pack very, very efficiently.
Consequently the Maggot Lair was an absolute breeze for me with this build. The only real issues I had were with the packs of Undead Dolls in Durance of Hate L2, where I sadly died, but even that was mostly due to carelessness on my part, as I backed into a doll while running away from another pack.