Lack of attention to details

I had the same problem. What I did was figure out exactly where I was lacking details and develop strategies for each case. E.g. I was always missing the "except" in CR questions. So now, the first thing I do is read the question and rewrite it in my words with special emphasis on the except, and THEN read the argument. After deciding on this strategy, I found 20-ish "except" questions and worked through them in the exact order of my "strategy". I didn't even care if I got the answers right, as long as I worked in the order of read and rewrite question, read argument, guess answer, check options. After a while, it became natural to follow that order. I don't even have to think about it anymore and my carelessness rate on CR questions is now 0%.

Same issue in quant, I would solve a problem correctly and then forget that the question asked for half of a variable or a completely different variable, so I would pick the wrong option despite doing all the right work. I developed a similar strategy. Write down what variable is being asked first before anything else. Draw a box around it even. Then before picking an option, I had to read what I wrote and make sure it matched what I had solved. I drilled this strategy order with a few dozen questions and it became automatic too.

You know yourself best, figure out what you are doing wrong and fix it in a way that will be natural to you.