Simple, add more Negative Camber to the affected tires. If your track has several high-speed turns, add .5-degree more negative camber to that specific side. If both sides are wearing evenly, add .5-degree negative until the rounding mostly stops.
Additionally, setup can play a big part in tire wear. Roll Center, Track Width, Track Length, Springs, and Shock Rebound, etc... all play a part in traction and tire wear. When you don't have enough traction, the tires will wear greater as they push through a turn.
One last thing, your personal driving style could be the cause of the tires wearing poorly too. Some people oversteer their cars in the turns to compensate for a poor setup, or simply give the car too much power while going in or out of corners, causing the car to push no matter how good the setup is.