Park next too better cars.....
Kidding, if you have Halibrands you can use the U-shaped bicycle lock unit. Fit the U-shaped portion through the front wheel and use the locking mechanism on the inside of the wheel. The car can't roll as the driveline will catch and stopp the roll. Basically it makes it more attractive to find an easier candidate.
Also, place a battery shut off in hidden place. Renders the car unable to start.
Be insured eitehr way!