Are you level 26 yet? Once you hit 26, jump on destinylfg.com or .net, or reddit.com/r/fireteams and find a group to do the Vault of Glass normal mode raid. Raids are where the good loot is. The Vault of Glass raid armor will only get you to level 30 by themselves, and the weapons only go to 300 attack, but they're still very useful. Then once you work up to level 30, do the hard mode Vault of Glass raid, and the Crota's End normal mode raid.
Raiding is the best part about the game.
Also when you get up to around level 30, you can start doing the Weekly Heroic mission on hard (9 Strange Coins reward), and the Weekly Nightfall for a chance at an exotic armor/weapon , legendary armor/weapon, legendary engram, a bunch of ascendant materials, or a bunch of strange coins.
Rack up a bunch of strange coins and buy some exotic gear from Xur when he comes to the Tower. Or hoard your Motes of Light and buy an exotic engram when he sells them.
If you start getting a lot of legengary and exotic armor for classes other than the one you play with, create a new character of that class so you have a use for the armor. Level them up to 20 and equip the armor and boom, you're already up to like level 27 or 28. I started as a Warlock then got a bunch of armor to Titans and Hunters. Now I have a level 31 Titan and a 29 Hunter and I barely play as them.