I play him as a babysitter until I feel comfortable enough to go roaming.
Usually I hang back and snipe-stun and / or block so my carries can get kills / escape certain death.

When I get blink and manaboots the fun starts and I will show up to all teamfights to wreck havoc.
My warding starts mostly when I get blink, I usually try to rush it since I'm so much more effective with it.