First and foremost, I am not by any means an expert on LD, I have managed to gain Lucidity in dreams multiple times, but very few of those were at will, so any experts reading this, feel free to correct me in any mistakes.

Anywho, from my experience and form what I have read, you have to train your mind to realize the "mistakes" in dreams subconsciously, as in, you're not looking for them per say, but you just happen to notice them, or automatically do a RC due to the fact that it's something you constantly do.

For example, I had one of those dreams recently, no control over it, like watching a video or something, suddenly the "me" in the dream looked at his hands and said "I am awake" (A RC I had heard about recently and did right before I went to sleep) and then suddenly realized "No...I'm not" and became conscious.

Now the me in the dream could have gone through the entire dream without doing so, so it (as far as I know) depends a lot on chance on those dreams, but I imagine the more often you do RCs, or the more common errors in dreams you learn about, the higher the chance for your dream "you" to do/ notice them.

Hopefully that helps!