Complete Bounties for more XP
Once you reach level 4, Head to the Tower Watch and visit Xander 99-40 for bounties (rewards for completing particular challenges such as killing a certain number of enemies without dying). You can hold up to 10 bounties at a time. Bounties provide bonus XP. Every time, you turn in a bounty, the bonus XP is applied to the items you currently have equipped. I suggest getting Vanguard bounties early on because you can complete them as you go through the story missions. There are also Player vs Player bounties know as Crucible that you should play until your rank is high enough to buy armor.
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At level 20-26 you’ll need to buy legendary armor. Once you have your armor, continue to do play crucible bounties to level up your gear. With bounties you will level your new gear the fastest. If you run out of bounties, Tiger Strikes are very popular sources of more bonus XP. You should find a higher level friend to play with to complete difficult missions and level up even faster.
Once you reach levels 26-28, on this Reddit discussion hasCode suggests that you should be doing raid every week. You can request for help on/r/fireteams or destinylfg.net, chances are people will complete raids with you or help you get ascendant shards.
To get to level 29 and 30 you’ll need to max out your legendary armor and acquire an exotic helmet, this you can best find in Xur. Also frequently do hard mode raids with high level friends, ask for help here /r/fireteams or destinylfg.net.
Destiny – Expansion Pass – PlayStation 4 [Digital Code]