Here we go again.
There are basically three ways to level up in Destiny.
1. RNGesus: grinding for Blue and Purple Engrams and decrypting it to get Legendary and Exotic gears... you need luck to get a Exotic gears because it have low decrypt chances.
2. Buying: Just get enought Vanguard/Crucible/Faction marks to buy any Legendary gears or just buy Exotic gears from Xur.
3. Exotic Bounties: Just complete the three tasks of a Exotic Bounty to be rewarded by a Exotic gear.
I did not grind at all and got that:
1x Exotic from Blue Engrams
xx (ALOT) Legendary from Blue Engrans
1x Exotic from Purple Engrams
2x Legendary from Purple Engrams
2x Bought in Vangard using 130 Marks
1x Bought from Xur with 13 Strange Coins
1x Exotic Bounty
lvl 27 and close to lvl 28.. just need a Legendary Helmet (the only Legendary gear I don't have).
I just play what I think is fun 
Destiny loot system is great in my opinion... every single enemie have change to crop Engrams based on your level... high level more rare is the Engram you got (I started to get a lot of Purple Engrams after lvl 25 and close to nono Green Engrams).
It is not like others games that you need to beat a specifc mission or boss for that rare loot... any place or enemy can give you the loot you want 
