If you have the Top Dog Silver Pack DLC, this achievement will be made a world easier for you. A lot of players seem to have an issue obtaining this achievement, because Triad experience is earned much slower than Cop or Face experience. If you're having problems, try putting on a clothing set that boosts your Triad experience gain. Basically, you want to be pretty creative with your kills to earn Triad experience, so grappling into objects and vault kills are your best bet. You will automatically begin missions with no Triad rating, and you will have to build it up gradually over time. If you're still not level 10 by the end of the game, you will need to replay missions.