Legendary engrams drop very often now, so you will want to decrypt them 1 at a time and equip higher light gear, and decrypt again. Public events also give you marks for the first completion per character per day, plus a legendary engram. Archon's Forge also has multiple difficulty levels; green offerings are for 320 light, blue 340, & purple 360. If you don't have any offerings, complete a Quarantine patrol (they are indicated by the SIVA emblem) as they're a guaranteed drop now. You still can only hold one at a time, but they drop fairly often in the Forge when a group of 3+ ppl participate. 350 gear is also sold by vendors, but I'd recommend saving your marks for a Ghost. Tyra also gives a 350 artifact once per week per character upon completion of the weekly quest, which anything done in the Plaguelands will contribute to. Faction packages also reward at least 1 legendary item, but I recommend saving those until you get to 365 light. Once you're 350 light, the heroic playlist will become more manageable and the blues that are rewarded (only from the boss) will drop up to 365. Ghosts & artifacts also have a chance to drop. Skeleton key gear can also drop over 365, so save those for then. Also, be sure to share some excess loot w/ your other characters so they can level up w/out you actually using them. When you do use them, pool your engrams for your main for better chances at stronger gear. Hope that helps.