A general rule of thumb is to never mow more than 1/3 of the leaf blade off at any one mowing. Secondly, it is better to mow twice a week (during the active growing period) and always try to mow during the coolest part of the day. Lastly, the new mulching deck mowers are terrific as they return the grass clippings and nutrients back to the soil. By doing this you can help the land fills by reducing lawn waste and you can even save an extra fertilizer applications.
Set your thermostat as high as comfortably possible in the summer. The less difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be.