An instance of personification occurs in these lines:
If you can meet with Triumph and Disaster
And treat those two impostors just the same
This set of lines personifies Triumph and Disaster. It treats them as if they were people in 3 ways. First, they are given proper names. Second, the assumption is presented that they can be "met with" as if you were going to meet them for coffee. Lastly, and most clearly, they are renamed as impostors, a human ability to disguise one's self.
Here's another personification, a minute doesn't have the capability to forgive, people do:
If you can fill the unforgiving minute
As for simile, I can't find one that specifically fits the rule of a comparison using like or as. Maybe another editor will know something I don't. I think you could argue that there are instances of metaphor, and I think many similes include the word 'if', so there may be instances that are close, but not quite.