Just play the game.

To help get things started, save those legendary marks... The gear you can purchase is a good start towards leveling up. I'd maybe suggest buying a 280 ghost, as your armor and weapons will be changing pretty quickly for a while. Whenever you turn in engrams, put on the absolute highest level you have in every slot. If you have any strange coins you should buy as many three of coins from xur as you can. If you use one coin before a strike or crucible match you will start getting some exotic gear too... Gear you find that way will be at 290, although you can only have one exotic weapon and one exotic armor equipped at a time. If you are using three of coins, never use more than one at a time, and when you get an exotic engram you should stop using the coins for 15 or 20 minutes as it has a cool down period. Otherwise just do your daily bounties, do low level strikes, and work those 3oC. Early on, if you use an lfg site or the recruitment forum you could also get help going through the Vault of Glass and Crota raids... That will give you a shot at some year one exotics (which makes blueprints available) and materials you can use to level a faction, which also gives rewards. You should choose a faction in the tower if you haven't already. The last thing I'll leave you with for now is leveling gear. Make sure you have things equipped that need to be leveled before you turn in daily bounties. That's the fastest way to level things. Good luck!

For me is playing crucible but if that's not your things it's probably doing raids and strikes also strikes can give you some "strike exclusive loot that's good as hell"