I hope that this isn't in violation of the "no how-to DIYers questions" but I guess its worth a shot.
I work for a municipal park district and I am putting together a program for this winter’s maintenance training. Our work requires us to span a wide variety of fields although very large or difficult projects are usually contracted out. I am trying to put together a bunch of odds and ends that are considered important to know or at least have nearby. Some examples would be knots, wrenches that are the same in SAE and metric, extension cord length/gauge maximums, principles of geometry. I am on your forum hoping that you all will be able to assist me with some ideas from your area of expertise. The current knowledge of our staff ranges considerably from interns with very little experience to technicians with decades of experience so no tidbit of information is too small or too large. I'm also interested in knowing any mistakes that are commonly made. Like Otto Von Bismarck said "Fools you are... who say you like to learn from your mistakes... I prefer to learn from the mistakes of others, and avoid the cost of my own." Or in my case, because I've already made too many of my own. Any help you could give me would be greatly appreciated.