Get your items, maintain your range during team fights, look for picks with your ( E ) + a basic attack with Iceborn and Cannon for the massive range, and with still not enought, ward ( Q ) with the mouse on their trajectory.
Try to call your jungler to a unwarded brush close to lane ( that you used Lens or pinked with a control ward ) and go back to lane with your E, while faking that you're alone, by going towards your adc , not theirs, and when they're out of guard, try to hit them with your root ( W ).If the jungler has a easier to hit CC, wait to chain your root ( W ).
Also, after level 6 look even more on the minimap to know when to ult your team or even kill someone recalling, but don't forget, unless it's garanted, try to not ult only for picks only during 1v1's and 2v2's in other lanes, your ult shield is very usefull in those skirmishes , and often make a diference.