As noted by DarkJedi farm the Countess and kill ghost on your way to her, not only high runes but lower runes can be quite useful.
Nightmare Cows should be doable as well and while it can’t give you the proverbial good stuff it is pretty useful and allot easier when your not decked out yet and much of the good (not godly) gear can drop there.
Same for Baal Nightmare.
Of course I you can already do decent runs now or with minor upgrades Hell is a better place to farm, if you can’t no shame in doing some Nightmare to better prepare for Hell.
Good farming spots are all level 85 areas you can easily find and clean fast.
All act bosses you can get to and kill easy, with Andariel and Mephisto being favorites.
Andariel has very high drop chance and if you can run her with some mf comfortably it would be a very good one to farm some of the better gear.
Mephisto is an easy boss that can drop quite well and is easy to reach, if he’s to strong you can do the moat trick but Lightning and Orb aren’t the best skills for that so you would always have to take allot of mana pots.
Arcane Sanctuary is reasonably easy to farm with a lightning build and has nice drops and good rune chances (mostly because of the ghost but many nicely packed group you can kill fast from a distance.
Travincal is nice but I don’t think you would have a great time trying to kill the Council unless you have a tough merc and lure them to come with only a few at a time.
Shenk/Eldritch/Pindle in act 5 are nice fast trips, be warned though Pindle charges for allot of damage so open with FO for slow and do it last so you can leave game if you risk getting overwhelmed.
Normal items you should try to get is Occulus (Occy), “Spirit” Shield, Harlequin Crest (Shako), Skin of the Vipermagi (Viper).
Alternatives are plenty as you can mix and match allot, but basically weapons, armor, helm, shield that give most to the skills your using, while you have enough all resistance which is very important in Hell, defense is a nice bonus but should not be your main focus as you want to keep out of melee range anyway.
Faster Cast Rate you should aim for 105 or more, but everything above 105 does not do anything unless you reach 200, this does not help allot for Frozen Orb, but still very usefull so if you have 115 and a 10fcr ring you could replace that for a better ring without it and not lose anything.
Usually things like gloves Magefist or Trang Ouls Claw for the FCR or if you don’t need more just use best rares you have with a decent resistance.
Belts/Rings/Boots are often best you can find to fix any resistance problems, sure things like Arachnid Mesh and Stone of Jordan are very strong, but also very expensive and rare so if you get them nice, otherwise just fill in the gaps with these items.
Amulet +skills if you can find (or gamble).
Alternatively to the above is Belt/Amulet/Armor of the Tal Rasha set or the full Tal Rasha set, while not the very best these items are very good for magic finding and quite solid.
Since I am not sure of your exact gear I’ll just name a few “easy” items, you should be able to farm with little RNG that might help you in very short term.
Smoke: 2 Socket Body armor, all you need is Nef-Lum, make it in the highest defense Light armor you can find, if you don’t have any go shop in act 2 normal for a 2 sock non-magic breastplate.
Adds decent defence, but more important 50% to all resistance which you said you were lacking so this should help allot.
Splendor: 2 Socket Shield with an Eth-Lum, +1 to skills, bit of FCR, mana regen energy and magic find. Cheap and easy to get.
Spirit: If you can get yourself a 4 sock Monarch its the best shield you can get most of the time.