To me, "If" by Rudyard Kipling is giving advice about how to get the most out of life.
Each stanza is filled with paradoxes beginning with the word "if". Each if statement appears to be a contradiction at first glance, but take each one apart and you will find a proverb or wise saying: If you keep your head about you, when all about you are losing theirs and blaming it on you. This is not a difficult thing relate to. Most who have lived through middle school have experiences that can speak to this. Each "if" statement clearly presents a challenging balancing act. The first stanza really deals with social challenges, Being nice to others when they aren't being nice back.
The second stanza really focuses on setting goals and having plans but not becoming a slave to them. In this way, if things don't work out as you hope or dream, you can enjoy the journey. If you have ever had a dream and been consumed by it only to have it crash and burn, it is easy to see how that could ruin your outlook on life.
The third stanza focuses on taking risks but not whining about life if it doesn't turn out the way you had hope. The word "perseverance" really resonates to me in this stanza. Sometimes, the only thing one can do is stay positive and "keep on keepin' on". If you do this...well he tells you what happens if you do this in the final two lines.
The last stanza poses one final set of "if's" that focus on staying true to who you are and not letting others influence your character. I especially appreciate the lines
If you can talk with crowds and keep your virtue,
Or walk with kings - nor lose the common touch;
They clearly emphasize the importance of being who you are but appreciating everyone.
Finally, Kipling provides the result of doing all these things in the final two lines: If you do all these things and stay grounded, the world will be yours as well as everything in it and you will be a mature person.
"If", by Rudyard Kipling, is a set of challenges to poet's son, and by extension to all readers. It sets out standards for behavior that would allow any person to conduct him/herself in ways that Kipling is defining as being worthy of "the Earth and everything that's in it."
The challenges are delivered in the form of descriptions of how the person being addressed should behave "if" certain kinds of circumstances arise. "If you can keep your head when all about you are loosing theirs and blaming it on you" - the poet is encouraging the reader to not be swayed by the misguided sentiments and actions of others. The reader is being given the task of rising above fast and easy following of the crowd. Instead, the reader is to remain true to the nobler path of self-control, modesty, and dedication to striving for what is right regardless of the cost. In the end, the outcome will be recognition that "you'll be a Man, my son!" in the fullest and best sense of the word.