Every man should know:
How to communicate with others effectively. I have worked in customer service jobs ever since I started working. I have been a receptionist, a cashier, a salesman, a babysitter, and a leader in various positions in the Boy Scouts, and I have seen so many situations that got out of hand because one or more parties involved did not take the time to listen and understand the other(s). Whenever faced with a conflict at most of my jobs, it did not matter to me that others were waiting for service. I would call in the help I needed or explain to the waiting parties that I was handling the current situation in the best way I knew how and would be willing to help them as soon as possible. It was that kind of explanation that some would say is unnecessary that helped me excel in customer service.
How to rationally defend one's position. One should know what they believe and have solid ground to support the reasons why they believe what they do. I have seen many Christians who believe, but it is blind faith, of which there is no need when a perfectly rational support exists for their belief.
How to access information necessary for their goals and tasks. I don't know how to fix most problems on a car, but I know how to access the information necessary, and I know how to ask for help (and from whom I should ask help) for various things. I also know how to commit fairly simple processes to memory so that I do not have to call on those same sources of information time and time again.
How to maintain their own property. By "property", I am referring to those things a man owns. I believe a man should not own something that he does not know how to take care of, or if he is not willing to take care of it (even through outside help).
How to be financially responsible. Typically, "thrifty" does not describe me, but financial responsibility is something that I am learning. A man should have enough forethought and self-control to see what he wants for the future, and handle his finances so as to achieve those goals.
Common courtesy and manners. There is a time to tell "guy" jokes that--while morally clean--are of a decidedly more "gross" nature. I recall a particular joke that one of my youth leaders told about a hunting trip, and while it was not morally offensive, it did not go over well with some of the more easily disgusted members of the youth group. Every man should be aware of his surroundings and act accordingly, and he should learn common chivalry and manners.
How to be self-sufficient. Every man starts out single, and he should not assume that his wife will iron his shirts, do his cooking and cleaning, etceteras. Every man should know how to do simple repairs to his clothing (i.e., sewing a button back on), clean his own living space, cook his own food, do his laundry, etceteras. Those things which may be considered more "feminine" skills can come in handy for a man as well.
How and when to submit. Though it can be against our nature to submit to authority, the Lord tells us through 1 Peter that it is commendable when we submit, even to a harsh master. There is a time and a place to rise up and--like Dee Snider--tell them, "we're not gonna take it anymore", but there is also a time to lay low and simply get by. Wisdom will allow a man to discern the differences between these times.
How and when to defend himself and those he cares for. In my opinion, every man should have the knowledge of how to read a situation so as to avoid conflict, whether verbal or physical. One of the first things they taught me in martial arts is how to avoid fighting altogether. After we learn how to avoid fighting, we learn how to defend ourselves and those we care for from an attacker, with defensive moves (blocks, holds, throws, and non-lethal countermeasures). When it becomes necessary, we should also know how to fight back, but only to the point that our attacker will no longer wish to engage us. Every man should remember that all life is sacred and cannot be replaced, and we should do our best to preserve the life and well-being of even those we call our enemies.
How to provide for his family and others he cares for. Every man should find at least one skill, but the more knowledge a man can acquire in various trades, the better. My father is a prime example: he worked for the Air Force in computer science, but also had skills as a leader. Thus, when he retired, he was able to take on a corporate job as a senior manager. After he was laid off unexpectedly, he was able to fall back on his skills in horse training and ministry to follow the Lord's calling as a minister who uses a horse to teach others about Christ.
How to love. There is very little, in my mind, that is more repulsive than a man who thinks he is God's gift to the world simply because he is in love with himself. A man who lives with a selfish heart has little value to his family, his friends, his society, and his Lord. Every man should know how and when to eat humble pie, and how to love others--even if it means offending or hurting their pride.
That's what I can think of for now.