Regarding the science section, I personally found it best to go straight to the questions. Most of the time, you will not need to read the entire passage in order to answer the questions. This will save time, which is one of the biggest issues in the science section. You should definitely keep practicing and going over the problems that you had trouble with. Make sure you understand why you made that mistake (whether it was from not reading the problem right or not knowing where to find the answer). Once you know where your mistakes come from, you can focus on improving.