You get 1 experience point if you win a match in Matchmaking playlists (except for Action Sack). However, if you decide to quit out of a game there will be a 1 experience point deduction. For fastest experience gain, avoid quitting out games or betraying people, and make sure you win lots of games.
Experience points will only get you so far. If you want to make it to a "general" you must get a Highest Skill of 50 which can only be achieved in "Ranked" playlists such as Team Doubles, Lonewolves, MLG, etc. In order to fully understand how the ranking system works, and when you rank up, click here to see the chart that bungie uses to show when you rank up. If you have any more questions related to the ranking system, please feel free to send me an email.