When my husband and I first married, we lived in a small town where the houses were mere inches apart. So close that there was no space for individual garages, so everyone either parked their cars in side allies or on the street. This was new to me as I had previously had the convenience and protection of my own garage. But I'm a quick learner and after I was done whining about snow removal in the frigid mornings, I realized that doing these things would help protect my car from the elements:

Sun safety: I'm not proposing we lather sunblock on our cars, but the sun's rays can certainly damage the paint and, to a certain extent, the interior. To protect our cars' interior from the harsh sun, invest in a "sun shade." Not only does a shade keep your leather or fabric from fading, but it keeps the inside of your car cooler.

Steer clear of trees: Parking under a tree is never a good idea: falling debris can scratch, birds can poop, sap can discolor or stain! 

Cover up: Aiding in the preservation of the car's paint and your elbow grease is a simple car cover. For easy debris or snow removal, and to shelter the windshield, a car cover fits over the hood and roof for quick coverage and maximum protection.

Wax on: A layer of wax between a car's paint and the elements means the paint lasts longer and looks better.

Avoid busy streets: If you can park on a quieter street with less traffic, it's to the benefit of your car. Avoid bus stops, intersections, and otherwise congested streets to minimize the possibility of damage to your vehicle. 

Consider a carport: Depending upon where you live or rent, you may not have this option. However, if you can't build a permanent structure like a garage, consider installing a temporary carport. It's better than nothing and provides extra protection.