Reading fast is important but of course you should not read fast for the sake of reading fast, you should retain info as well. I am not a native speaker and here is what works for me:
- Read carefully, underlining names, opinion cues (some scholars, some experts, that dude etc.), certain phrases (for example), words reflecting author' opinion (X rightly thought that etc.).
- Read once, return to the beginning of a sentence only if it made no sense at all. (This happened to me once in 33 PTs, a passage about someone's ideas about legal objectivism and some such? Some analogy about winning a game which had illegal rules or sth, cannot remember now)
- When you get to the questions, the question forms are pretty much same for all passages, if it asks main point think about the whole passage, eliminate answers that encompass only one paragraph of the text, unrelated ones etc; if it was a passage with a lot of opinion shifts, counterexamples and what not, usually the longest answer wins. (Despite evidence to the contrary bla bla bla yarr yarrrr )
- If it asks author's opinion, go to words you underlined, let us take a look, (Newton was awesome), firm support or something like that should do it.
- Similarly just refer to words you underlined and related areas of the passage that you imprinted on your mind during your first pass, that's it.