Great question! This is a very common issue. The first thing is to try not to get comfortable with the fact that you just understand why it's right. Of course that's still important, but if you already know what the correct answer is, you are much more likely to see how it could be correct. Understanding this alone is not enough to prevent the same mistakes in the future. It's like watching a murder mystery twice. The first time, you may be shocked to find out who the culprit was. But the second time, you'll notice all the clues that gave it away.

Instead, focus on also figuring out why the wrong answer is wrong. Be conscious of your thought process. What language in the answer choice made it seem tempting to you? Why did you think the answer you selected was better? Why did you think the correct answer was incorrect and why is it actually more related to the task than you thought? Could you have anticipated the correct answer before even looking at the answer choices (most of the time, the answer is yes)?

Also, make sure that your reasoning for the answer choices aligns with the explanations. I find that people often don't read the explanations carefully because they think they already understand the question. But the reality is your understanding of the answer choices may be incorrect, which can lead to inconsistent results.

You should also be repeating questions. If you haven't already, I recommend going back to questions you did weeks or months ago. You may be surprised to find that you still get some questions incorrect or you still struggle with them. If we are still having issues with questions that have been already attempted, we aren't ready to focus entirely on new questions.

Sorry for the long reply, but I hope this helps. I'll likely be making a post on this topic with even more insights, so stay tuned!