Also, make friends with your neighbors. Discretely, find out who could be of help or like minded and also, those you need to keep and eye on. In my apartment complex, a few like minded neighbors and I walked the perimeter finding secure points and those that needed more work. We also have a lot of older people that know canning, sewing, etc. In a perfect scenario, we could be a self-sufficient area with places to plant crops, water nearby and enough people to secure our assets. I try to think of it more as a community than as just as lone-wolfing it.
But of course, when the SHTF all of that could be pipe dreams.