Completing bounty quests is your best bet for unlocking tons of extra perks for those uncommon, rare, and legendary items the Guardians tote around. You will find the different level and different types of gear (Armour and Weapon) throughout your gameplay, like; basic, uncommon, rare, legendary, and exotic. All other gear except Basic Gear will have the perks that you can buy or unlock once you have the max level of XP for that perk.

By Completing Bounties

Completing the Bounties you will get the huge amount of XP as a reward, which is more enough to level or Rank up your armour and weapon that you have equipped. For that just follow these easy steps.

First of all you need to you need to equip that armor and weapon that you want to rank up. Now turn in completed bounties to get the instant infusion of XP added to your character level progression, and to any gear. Talk to the robot in the Tower once bounties unlock to start several at a time. And if your armor and weapon is already fully rank up you can bring up the other gear to rank up.

Watch the video below to get the more help.