Your main spammable is Surprise Attack. Always use this whenever you have nothing else to do.
If the boss has les than 25% health, we use Killer's Blade instead of our normal spammable.
Keep Barbed Trap on the enemy at all times to deal damage and also give you the Minor Force buff.
Keep the Twisting Path AOE (area of effect) ability active at all times to also deal damage to the enemy.
Use the Incapacitating Strike ultimate whenever it is ready, boosts all your damage by 20%.
Keep the Relentless Focus skill active at all times. You can use the spectral bow whenever it is ready or after you use Incapacitating Strike. In execute we just keep the skill active but don't want to activate the spectral bow anymore. That way our execute ability benefits from the extra damage the skill provides.