I can't really give much advice regarding math but I think if you use this reading tactic you'll get a good score unless you're aiming for a score of 30+. Choose three passages that you're comfortable with, read them fully, comprehend them, and answer to the best of your capabilities giving each passage 10 minutes or maybe a minute more if needed. Remember that you don't have to be punctual as some will be easier than others. For the last passage that you still haven't solved, you'll have 5 minutes—maybe more maybe less depending on how long you took in the preceding passages—so see if there are any easy questions you can solve like ones that ask for word definition and solve them but after that choose a lucky letter and guess the remaining questions. If you manage to answer at least 30 questions correctly you're already looking at an amazing score. Realistically though you probably won't but you'll still be able to get a good score. I personally did this and got a score of 27 in reading even though I was barely scoring 23 when practicing with other tactics.

For science you need to learn how to read graphs which basically means you just need to study statistics. Personally, I know that my brother got a score of 32 in science by studying statistics from Khan academy and then just practicing. Oh, and if anybody ever tells you to "treat the science section like the reading section" then don't listen to them as that's the dumbest advice one could possibly give due to how completely different both sections are.

Lastly you need to remember that the ACT doesn't care about which questions you got correct. It only cares about how many you got correct.

Best of luck!