A level exam technique

Hi, a common issue I have noticed in my exams practice both in school and at home is that I lack in exam technique, but can easily answer the questions themselves. This has meant at the start of the year I lost marks because I simply did not show my working to the degree needed but got everything correct, and currently, I lose marks because I write every little step down, which means I get less thinking time, so I do worse in the accuracy of my answers. I know that I can answer the questions themselves as I could when I did not show my workings as in detail and focused on just getting the answer, but for my A levels especially (Maths, FM, Physics), it is an issue, which means although my grades are good and at A's and A*'s, they could be much higher if I could spend more time on the questions instead of writing every little bit down as I currently about the same time thinking in the exam as I do writing so I do not lose method marks. Is this overkill? Or do I just need to write the critical steps and skip over all the rearrangements, as honestly because I write them out so much, I am more prone to arithmetic errors as well.