Specialist functions by giving the player a new perk every two points, up to a max of three perks. Once eight points is achieved all the perks become available to the player.
For a big K/D try having an assault rifle with a silencer and an optic. Base perks, Scavenger, Assassin, Stalker. Specialist Rewards; Quickdraw, Slight of Hand, Blast Shield.
With this setup, a more conservative approach is recommended after spawn, but the focus is the ability to be more aggressive with more rewards, the first two having an emphasis on speed, and the third letting you muscle through explosions that could kill you during an attack.
More strategies to come.