I have time now to do a more thorough analysis of Airianna's (rather impressive) post.
Airianna Valenshia wrote:
Girls tend to give guys female emotions. I’m not saying guys are heartless, soulless, or never cry. They aren't and do. However, their response to a situation is much less fueled by their emotions than the response of women. Emotionally, men and women are fairly similar. They just show it in a different way. Generally, women tend to externalize their emotions. Men tend to internalize them. A girl will come home and cry because someone was mean to her (this is an exaggerated example, cause I wouldn’t do that) whereas a guy would stew on the problem. Perhaps an honest male character would be one who thinks about his issues, but tends to emote them less visibly.
The two things most likely to make a man cry are: The loss or suffering of a loved one or other innocent person, or being worn down by a long struggle of some sort. Generally situations cause men to brood. Men are more likely to cry in the presence of women than of other men. Men are unlikely to cry in the presence of a woman, however, if they feel that the woman needs them to be comforting. Men can suppress their grief in most instances, either hiding it or turning it into anger. Men sometimes deal with grief by staying busy.
Airianna Valenshia wrote:
Guys are also physically stronger. I’m sorry, you can’t argue that. Now, I was a farm girl. I could throw 50 pound hay bale no problem. Some city boys, who came out to work with my Daddy, couldn’t. This wasn’t because I was “stronger”. This was because I was accustomed to the work and using those muscles, whereas they were not. They could still probably overtake me physically because guys are created more physically powerful than women.
That pretty much says it all.
Airianna Valenshia wrote:
Remember when you are writing that guys brains function very logically (I’m NOT saying here that women’s do not). They also respond to situation very quickly. The Lord has designed guys brains to run through a rapid fire thought process in and instant so that they can fly into action. Girls tend to dwell on a thought process more. Guys are also more prone to take risks and exceed their limitations. They function much better on adrenaline than women. They are designed that way.
I'm not so sure about this one. I think it widely varies. Men are divided somewhat into leaders, thinkers, and followers. The leaders think things through fast and jump into action. The thinkers muse on a problem for awhile. The followers look to a leader for direction, though some will jump into action if there is no one to guide them. I imagine most male protagonists would be leaders, and so would think as you described. Also, many followers or thinkers have the potential to become a leader if given enough time or the right inspiration, and this could make an interesting character arc.
Airianna Valenshia wrote:
Think of these characteristics when you are writing your men. Confidence. Competence. Competition.
Most importantly, competition. Not all men are confident or competent in all areas, but they are all competitive.
Airianna Valenshia wrote:
Another big thing to remember is dominance and hierarchy. Guys function off of a “pecking order” It's kind of like the Alpha Male syndrome. Guys like to know who’s who in this system. When men meet other men, they look at the other guy and asses them, subconsciously. "Can I take him if I need to? If so, how?" I’ve found this is automatic. They don’t really literally think and dwell on this. It may sound crazy to some girls, but it is true. Why do you think young boys thrive so much on horseplay and roughhousing? They are learning the physical skills of strength and domination. They are preparing for their role as the protectors, the combaters.
All of it, including the "Can I take him?" part, is true. Men in general are dedicated to the idea of being a protector. They're always thinking of how to protect themselves and their loved ones in various situations and deal with various threats.
Airianna Valenshia wrote:
To whine and moan is weakness. To overly show fear, is weakness. So guys tend to suppress these things. They would rather jest in the face of fear, then allow their oppressor to feel power over them. But I already talked about this in the torture thread, so I won’t go into any more detail on this.
Guys may whine and moan to sympathetic girls or other guys who are their friends, but only if they don't feel strength is needed in that moment, and they would never show the same vulnerability to their enemies.
Airianna Valenshia wrote:
I’m not saying that all guys are like this. Also, guys have these characteristics in varying degrees. However, I hope this helps some. Obviously guys are so much more complex than these simple things, but it is a start.

True. I feel inadequate to give a comprehensive overview of such a complex subject, even though I am a guy. However, I will answer questions as best I can, and maybe some other guys will offer to as well.