My strategies:

Main bike is (fast/good/pimped) folder that i can take with me inside most of the time. Plus even if i do leave it outside it's smaller wheels make it look 'weird' and presumably less attractive to bike thiefs.

When i still used racers and other bikes i simply made sure they looked like sh17. and had good locks. I love to cycle and cycling on a bike i love is what it is all about for me,.. but it is not about the Bling so much...

So i would leave a bike worth $ 1000 or maybe even $ 2000 locked up on a rack with 1 or even 2 good locks as long as it looked like an $ 50 ride. It is easy to make a bike look like a$$ (without affecting the performanc at all). And if you are handy and willing to be creative it is even not so hard to make a bike look caca but make sure all your mods are reversible. For example using black bar tape to cover all the tubes, sprinkling gravely water on rims to simulate rust very effectively etc.

Another trick (non-reversible) i have employed is using a centerpoint/engraving machine to etch my name or ZipCode in Top tube in large letters then painting that in bright white.