Although the heat is on it's way out this is not the time to get lazy and let the garden go. Watering is still very important if you want your garden to produce well this fall season. It's a good time to plant new crops since the heat won't wither them when they come up.
A thorough weeding of the garden is a good idea too and needs to be kept up since the heat won't keep them down either. It's now prime growing time and there isn't any time to loose. Before you know it we'll be having cold snaps and harvesting of late vegetables before the first freeze.
If you're stuck on ideas of what to plant here's a few ideas:
Beans will grow quickly and can be harvested throughout November if you get them in the ground now.
Carrots will always be a good idea and can be harvested around the same time.
Winter squash and possible summer squash should do well.
This is also a good time to get an herb garden started if you don't have one already. Many herbs will grow throughout the year but now is a good time to have them root well.