1) No parking in the street (it hinders the snow plows' ability to plow) - park in your garages and driveways; if you have more cars than parking spaces at your home, consider asking a neighbor if you can park in their driveway while the plows are out, or park in the pool parking lot.
2) No shoveling the snow from the driveway into the street.
3) No driving through snow banks (this sprays the snow back into the freshly plowed streets and creates slick spots).