Beware of contests which require you to put up money to win, even if there is a guarantee that you will be a winner.
Park on a busy, well-lit street, or if you’re in a parking lot, look for an active area that is well illuminated. The thief probably doesn’t know who owns the car, so he’ll stay away when anyone’s near it.
Although locking your car cannot guarantee it will never be stolen, you’ll certainly deter a thief. Getting into this habit will provide added security.