Owning and parking a motorcycle in a city like New York leaves it vulnerable to lots of incidentals like thieves and parking mishaps. Resist the urge to park your motorcycles between two tightly spaced cars. A lot of people are not used to looking out for motorcycles and may accidentally or purposefully knock it over. Making sure there is space for your bike will help keep it safe.
Also while parking, try to use a cover if possible. A lock and chain will always help, but the combination of two will help to deter thieves better than one by itself. When choosing a parking spot, try to select a place that will either have very high foot traffic that will deter a thief, or a very low active area so that it is not visible and vulnerable to potential thievery.
Some other tips when parking a motorcycle is to make sure that you back it into a spot with your rear tire to the curb. Not only does it make it easier when it's time to leave, but here in New York, it's required by law. Making sure you park it at an angle so the front wheel is tucked in away from traffic will also keep to deter it from getting knocked over by passing cars.
Another handy tip is to carry a kickstand puck or, here in New York, you can find any number of crushed soda cans or bottles to put underneath your kickstand. On a hot day like today, asphalt tends to warm up and get soft. Coming back to your bike and finding it on its side is not a happy experience for a new rider.