Tier 12 Gear is something that people try to aim to have when they do PvP, to have maximum performance with the fastest cooldowns.

This is a trick i do with the Days of Iron Gear. You just get the reward over and over again until you get the max roll. You can check your roll via Destiny Item Manager, or know it asap when you see it , after a while you will get used to it.

Try to keep gear that is above 96% roll, and you should be a Tier 12 very fast!

EDIT:
You will know the max rolls asap you see them, but if you dont know them there they are:
Level Helmet Gauntlets Chest Legs Class Artifact Ghost
335 46/46+19 41/41+17 61/61+25 56/56+23 25/25+10 38/38+42 25/25+10
Credit/FullPost: Reddit Post for Max Rolls