Once level 20 purchase a cloak or "accessory" your guardian uses and sport it during crucible matches to level up for that faction. There is some faction gear that doesn't require a faction level to purchase it's on the very bottom row under armor, the last two items on the right only cost glimmer (2500) and require level 20. [b]Here is a video explaining it further:[/b] https://www.youtube.com/watch?v=F7HRgOwzr_M