I read somewhere months ago that if u keep playing the same pvp game modes, let's say clash, over and over u get an increased chance of gaining tournament tickets, the better you play the higher the chance. Also when u have the tickets new playlists appear in the crucible game selection screen, which can only be entered using the tournament tickets. If u get chosen for this playlist you can win - Unknown rewards, but you will be up against a much harder group of players :) hope this helps