get a Hyper Optic tint to block out some of the sun and you can also use one of those windshield shades
but what I usually do is as I'm walking towards car hold the open car button down on the key fob so all the window will go down as I'm walking towards it.....also I think there is an option in the Idrive that turns your air on a timer to keep the car cool, not sure if I'm correct since my old bimmer was pre Idrive but playing around w/ a friends Idrive I thought I saw it under the climate menu