Hey guys, I know I should read articles, guides etc but I just need short and quick answers.
I have all classes at 75, trooper/commando, sage healer, assassin operative or whatever thery called. I need guid on which stats should I focus, what gears and how can I get them after 75 and what is the most common/best builds for pvp if there is still a difference. And what OP s there now, any guide for them? Etc.. Any help is a welcome one, I'm active on both side, it was not my choice to take this year+ long break but I'm back finally...I "returned somehow" 
#Returning play
feral veldt
regal holly
Get to 80 first, then you can worry about gear. 80 is the current level cap, so it's where you'll be gearing for endgame. There is no concern for gearing prior. The standard armor from loot and rewards is enough for story content, and FPs bolster you if you play those. You cannot do MM FPs or any ops before 80, so there is no need for best of the best.
All your DPS classes need 110% accuracy. Alacrity should be hit next, though I don't have the exact number. This is around 2200. Last everything else should be crit.
Your tank and healer should be okay at 100% accuracy. Tanks get a passive accuracy boost, and healers will spend more time healing players than fighting bosses. Players don't block/dodge healing, so there's no dire need to boost the accuracy past 100%. Your healer needs more Alacrity than DPS players, again I don't have the sweet spot number as I don't play healer. Your tank should focus on Defense and Shield Absorption.
Ideally, gearing tips is probably more suited for a guide than a quick discussion as there can be a lot of depth to it.
Gearing is a long grind. The first step is to get 320 armor, your next step is to obtain a 330 porotype gear piece, while also upgrading your gear so your overall rating is 324. Once you do that you'll unlock Hyde and Zeek and you'll begin making your first set of 330 prototype gear. From there, things only get harder as you'll need to do HM and NiM Ops for anything better.