Stake your tomatoes and have them grow vertically. Tomatoes on a staked plant are larger and ripen earlier than those on a sprawling plant. Good air circulation around leaves and fruits of upright plants curbs disease. And fruits held high are free from dirt and slugs and out of reach of those pesky, but adorable chipmunks. Here is a good example from the garden:

Tie the vines to the stake with a piece of cloth to avoid cutting into the stem.

Confine each plant to a single stem by removing all suckers, ideally before any are an inch long. A sucker is a shoot that grows from a bud originating at the juncture of a leaf and the main stem. Go over your plants at least weekly, using your fingers to snap off each side shoot. 

Inspect your plants for pests and remove them, spray with cayenne flavored soapy water when the sun is high to reduce the risk of powdery mildew forming.

Water. Keep your plants moist down to 6 -8 inches in the soil and with this heat you will harvest a bumper crop! Watering slowly at the base of the plant is preferable to watering the whole plant to prevent mildew.

Air-flow management. Remove diseased leaves and discard in trash. Not only will your plants be healthier, but they will get the needed air flow to stay that way.

Mulch will help hold in moisture, reduce weeds and help prevent bacterial and fungal disease.