I really wouldn't worry too much more about theft simply because the car is an auto, but if it's got keyless entry and/or keyless start then you should get a faraday bag to keep the keyfob in. Other deterrents include steering wheel locks and immobilisers. A car tracker might be worth investing in, depending on how much you want to spend and the likelihood of theft. If you park on the road, park somewhere well lit near other vehicles and near houses or businesses if you can.