That poem doesn't need anything else (well, maybe some punctuation for those of us with dyslexia). If it is a school project for you to expand this poem then I do have one suggestion. Make your verse a story about someone who followed (or didn't follow) the advice. Good luck.

Its all in your state of mind;if you think you can, you can. Perspective is the key.

I have always liked poems, one can use the thesis statement as a conclusion. I believe it's fine as-while as is, but here's a thought.

This is the full poem :

You Can If You Think You Can!

If you think you are beaten, you are,
If you think you dare not, you don't.
If you like to win, but you think you can't,
It is almost certain you won't.


If you think you'll lose, you're lost,
For out in the world we find,
Success begins with a fellow's will.
It's all in the state of mind.


If you think you are outclassed, you are,
You've got to think high to rise,
You've got to be sure of yourself before
You can ever win a prize.


Life's battles don't always go
To the stronger or faster man.
But soon or late the man who wins,
Is the man who thinks he can.


C. W. Longenecker

'I think I can? I know I can!'