My main goals would be to destroy enemy buffing stations and turrets.
Most of the time I would be running with a medium capacity, medium damage, medium recoil, suppressed pistol.
Most of my time done will be close range melee-pistol combonations, that way the enemy will be right there for me to interrogate, then get a disguise from.
I will never touch any other class other then operative for two weeks playing the game, I will also use proximity stickies to my advantage when the enemy is planning to plant/defuse/capture/hack an objective point.
Also, I will try to maintain being as light as possible and be crouched and only use SMART... when it is smart to do so.