Your best bet for this trophy is to decide from the start of the game whether you want to go for an Evil Karma or a Good Karma game.
Make every decision 100% towards one side.
There will be several missions that make you decide whether or not to go good or evil.
Generally speaking, do everything
BLUE and avoid everything
RED.
When using abilities:
SmokeUse your smoke bomb and cause enemies to cough, then press
to subdue them.
NeonUsing your neon beam shoot for the glowing blue legs of the enemies to subdue them
VideoThere are also events that appear around the city that help towards good Karma
-Busting Drug Dealers
-Saving conduits
-Healing injured civilians
Do your best to not kill enemies and always try to subdue them. Knocking them out with punches or shooting them won't count as evil karma unless they are surrendering to you.
Complete your first playthrough with one sided karma, then restart and play a game on expert mode focusing on the opposite karma to earn the platinum trophy for this game.
Personally I chose Evil Karma for my first playthrough, and then Good Karma for my 2nd playthrough on Expert.