General care for your concrete:

Stay off it
- for at least 24 hours before walking on it
- bikes, roller blades, skate boards for about 3 days
- automobiles should stay off for about one week.
There is no need to water down the concrete if it gets hot. This is an old school train of thought and it actually does more damage than it does good, due to the fast contracting that it causes. It is better to have slower temperature changes.
It would be a good idea to seal your concrete in the fall by mid September to help prevent against salt damage and the freeze/thaw cycles that we experience in Minnesota.
Even if you do not put salt on your driveway, there is salt on you vehicles from the roads that can cause damage to your driveway. It is a good idea to keep your concrete as clean and dry as you can in the winter, especially the first year.

To summarize, salt, moisture, and freezing temperatures are new concrete's worst enemy.