“I keep making the same mistake over and over.”
You're practicing the guitar. You're trying to play a song while your friend listens, but every time you play it you get one particular part of it wrong. You say this about your mistake.
I keep making the same mistake over and over.
To "keep" doing something means that you continue to do it. You do it again and again. For example:
That guy keeps looking at me. What the hell?
"Keep ___ing" is used in normal spoken English, and can also be used in writing. But if you're writing a formal essay or speech, a better choice is "continue ___ing".
To "make a mistake" means to do something wrong or incorrect. This can be used for a lot of very different kinds of situations, including:
- getting the answer to a homework question wrong
- cheating on your husband
- telling a coworker the wrong information
"Over and over" means "again and again". You repeat "over" two times because to "do (something) over" means to do it again one time. To do it "over and over" means to do it many times.
"Again and again" and "over and over" are similar in meaning. But "over and over" sounds like something that's more work and harder to do than "again and again":
What wears you down is when the same mistakes get made over and over again.
It can be boring to do the same thing over and over again.
A good speaker understands the power of a simple message that is repeated again and again.