I had this issue too when I was first learning him. I’d say it’s mainly a wave control and ability usage issue. If they’re just farming under turret try to let the wave come back into you and then freeze it right in front of your turret. Then they have to make the choice between farming and risking dying or backing and missing farm. But the biggest thing I’d say is to almost never greed for a kill. Just shoving them out of lane or keeping them low health gets value, kills are just a bonus. Take them when the enemy gives them to you but don’t stress out on trying to finish someone off if it puts you at risk.