Exotics, ranking up your vanguard/crucible rank, luck. I think the best way(if you're a lower level) is to grind out your vanguard rank. Once you hit rank 2 you can get armour. Once you have the rank, grind out on marks. Best way to do that is to do Vanguard ROC, or Vanguard Tigers. You get 6 each time and 25 rep. You can only get 100 a week, if you didn't know. I would recommend an exotic helmet, so it's easier for you to get to a higher level fast. To get commendations, once you hit rank 3 you get one and so on and so forth. You use the commendation for the chest piece. Let's say you have your exotic helm and all legendary armour. You upgrade to the part where you need shards. If you are new, I would say do the Vault of Glass on normal to get those shards! It is super easy to get the shards. For an exotic shard, you need to dismantle an exotic of buy one from Xur for 7 coins. I hope that answered your question, if you need clarification, just ask.