1) Trusting the wrong people:
In a group of larger than (so and so) people, one has to be aware of individual ambitions. This is not to spur paranoia, but to let looses and understanding that our generations have been taught to think primarily of themselves. Being a good judge of moral character is paramount to sustaining a good relationship as a group.
2) Wrong signs:
I disagree with broadening the watch at various news sources as those that have the most shock factor are propaganda by the liberal/socialist governments. however, overreacting or underreacting is as much an internal threat.
3) no flexibility:
This is absolutely true. There must be a contingency for every contingency in every scenario. Nuclear, Biological, Chemical, and Militarily Invasive. At least two, better three or four contingencies per situation based on your area's topography and demographics. It is alot to muster so in my opinion, the most possible contingency should be memorized and the rest written down and carried should such an event take place. These contingencies should encompass the weakness of the other and overlap with a final universal plan should the "none-of-the-above" happens.