i've talked with actual thieves about this (dont ask, lol, but completely legitimate situation).
Both house thieves and car thieves.
Whatever they want, they will take, period. They will take it on a flatbed if they want it.
From the mouths of thieves, they report these things keep them away, in order:
1.) LIGHTING (obv at night)
**most home burglaries occur during the day when you are at work though**
** park in well lit areas on busy streets** duh
2.) Something noisy - alarm, dog, etc.
**the cheapest car/home alarm with the LOUDEST loudspeaker AND proper install (wires run in factory channels and protected by steel plate where needed -- so they cant be cut), and hood lock (so battery cant be disconnected) are far more important than an expensive alarm.
3.) dont advertise (ie, dont leave nice things on the front seat, dont leave your new lawn tractor parked in the front yard all week).
All thieves follow the basic laws of physics. They will follow the path of LEAST resistance. You dont need to be "thief-proof" (no such thing) you just need to be more inconvenient than your neighboor!