How did Kipling express his thoughts on manhood in his poem "If"?

The poem is a father defining for his son the qualities of
a good man.. He is setting the parameters or boundaries for his son and giving him a
goal to achieve.  The poem deals with life’s  challenges and how to deal with
them.

Stanza one deals with being confident about the
decisions you make and taking responsibility for those decisions. If others, who cannot
take that responsibility for themselves  react negatively, you will be patient with them
and not reduce yourself to their level by telling lies or dealing in hate. However,
don’t ever think you are above anyone else. 

Stanza Two
 states that it is good to dream, but don’t let your dreams control your life.  It is
good to think, but don’t just think and not put those thoughts into action.  You will
experience triumph and disasters in your life, but don’t take them seriously because
they are not the substance of life, they are the extremes.  If you hear things you said
misused  or things you have done destroyed, you need to be able to pick yourself up and
rebuild them with everything that you have left in
you.

Stanza Three counsels don’t be afraid to take risks
and possibly lose everything. If you do lose everything, don’t talk about it, just start
all over again at the beginning.   When you are tired and exhausted and your body just
feels like it can’t continue on, use your mind and your will to tell yourself to “Hold
on” and persevere. Push through it.

Stanza four deals with
a person’s reaction to others.  You need to be able to talk to large groups of people
and yet not let them influence your belief in what is right,wrong, moral, or immoral. 
You need to be able to walk with men of power and influence and yet not forget the
common man and his needs. You need to know yourself and your beliefs so well that
neither your friends nor your enemies can hurt you because you know who you are and what
you stand for.  People can depend on you, but don’t let others become too dependent on
you. You need to live every single minute of your life to the fullest.  If you do these
things, then the world is yours, and you will be  a good man.