In your early laning phase, you want to play safe and avoid as much poke from enemies as possible. Focus on getting your CS to earn more gold. Try poking with your Q. Use E and then AA when the enemy is beside the dagger and quickly drop your W and walk back to safety. Having Sheen or activating Tiamat would help you deal more damage in this short duration.

During mid-game, you would be able to deal more damage with Trinity Force. Entering a duel with E and quickly hitting an AA would deal a lot of damage on squishy match-ups. Drop W immediately to get an E reset while simultaneously using Q to set-up another dagger, which you can pick up to catch the opponent when he tries to escape. IN this stage, you would want to roam more often and assist in taking down squishy enemies, especially in bot lane to gain more gold. Always remember to drop wards while roaming.

During late game, you would want to stick with your team and try to hunt more opponents down. You can also choose to side push other lanes since you have high damage, quick attack speed, and bonus damage from Trinity Force. During team fights, you would most likely wait for an engage from your team, or choose to engage on your own by using E on a target you are guaranteed to kill. This way, you can reset your abilities more efficiently and focus on another target.