A knife can be used to make fires, shelters, weapons, traps, and most of the things needed for survival. With a few tools and some practice, anyone can have a workable knife (or chisel, hook, hinge, or any number of other tools and hardware) in a few hours of work. Besides the usefulness of the self-fashioned tool, it will bring a great amount of satisfaction and pride. The skill of blacksmithing will also put you in a very important position, should circumstances be reverted to post-civilization conditions. Your skill and handiwork will be in high demand.
Charcoal can be made very easily. There are some excellent websites on building a charcoal retort– a simple arrangement using 55-gallon, steel drums. I personally use a very basic method. I buried half of a 55 gallon steel drum in the ground. I start a fire in it and load it with wood, even piling it up over the top.