For reducing careless mistakes, you have to figure out why those mistakes are occurring. Personally, I found that I tended to make more mistakes due to losing focus and so to resolve this issue, I would make a conscientious effort to state what I was writing.
Another reason for making careless mistakes could be due to doing too many steps in your head at once. For example, doing all the algebra to find the inverse of a function, and domain/range all at once. So to resolve this issue, I would recommend just writing down each step at a time, even if it takes a bit longer.
Also, if you have a time, I would highly recommend checking your answer after doing each question which could be through ensuring each step is correct, using your common sense (e.g, you end up getting a negative answer for time) or, try doing the question with a different method.