do your exotic quests one at a time everytime you bring up your levels do more events to bring everythign else up and once you stop moving forward do another exotic quest. Pair that with powered engrams from milestones you will max in a few weeks time
now that you are 280 you can get LEGENDARY MODS from the gunsmith. Make sure all of your items have a mod on them including weapons as that will sky rocket your light.
Raid, weekly challenges that offer powerful engrams, Heroic event farming to try and get exotic engrams, and your weekly nightfalls and trials of the nine challenges. Good luck.