Imo the best way to start your journy past 20 is one of two ways. What I did is I got my vanguard rank to 2, then bought a couple pieces of vanguard gear, waited till o had enough strange coins/motes and got an exotic from xur. The other way is to be crazy lucky with drops from strikes (and then hope it randomizes to your class) or with crucible rewards. My luck is bad, I expect to see a lot of sparrows through my VoG runs lol...