max W (snowball) / 1 point in Q/ 1 point in E / max Q.
just step back, build momentum on your snow ball and just smack enemy team with it over and over. you'll win trades. your ADC will just auto-attack enemy that is knocked up and continue to do this over and over. they literally can't do anything. use your consume to heal yourself after you engage, and just walk away.
if enemy mid-laner is over extending, you can run snowball down river fairly quickly due to runes, and gank mid. repeat this process, literally win the game if your team have a brain.