I keep taking practice tests, but my score never seems to shift from around a 25 on the Reading section. Going straight to the questions didn't work at all for me. Should I just read the whole passage very fast first? Every time I take it I freak out about time...got any tips for me?
Skimming the passages first will probably be the best method for you based on the issues you're having. The best way to skim is to read the introduction and conclusion of the passage along with the topic sentences of each body paragraph. This will give you a sense of what the passage is about without taking up too much of your time.
On your first pass through the section, skip any questions that you can't figure out within 30 seconds. Lingering on hard questions can be problematic on such a fast-paced test. However, you should definitely make a point of revisiting any questions you skip initially. No points are taken off for incorrect answers, so it's in your best interest to fill in a bubble for every question.
I'd also recommend starting with whichever passage you find easiest to digest. It's best to answer the questions that give you less trouble first so you're not thrown off your game by challenging material early in the section. If you're more interested in science, for example, you could read the Natural Sciences passage first even though it's the technically the last passage in the section.
You should also take note of the types of questions you're getting wrong on the section to determine if this is just a time issue or an issue with understanding certain kinds of questions. Remember, the answer will always be supported by direct evidence in the text. Eliminate any choices that don't adhere to this rule. Check out this article for more detailed advice on how to stop running out of time and improve your Reading score.