I look at what the perks are on the legendary gear. Like helments for my titan, I like to have perks like non guardian kills helps boost super back up. So I like my variks helment I got with armor core that's 42 light lvl. My leg armor I look for more heavy ammo but the legs variks sold didn't not have that perk so I ascended so crota legs to 42 light. And so on for the other peices. If you like auto rifles then hunt for armor that gives more auto rifle ammo and faster reloads on autos. After I have a few sets of what I want perk wise then I start looking at intellect and disipline and strength stats. My warlock I always run self res so having high intellect does appeal to me so I try for disipline and strength because most of the time I just hold my self res as a backup. Kinda long but hope this helps.