This is all descriptive of my current thoughts on the matter, not prescriptive - I don't assign high confidence to my effectiveness in this area except when it comes to the scientific paper part. When it comes to that I am almost sure my way is both distinct from and superior to what most people at my scholastic stage do.

The "how to read" guide is complementary to the "how to write" guide that your author read.

There's lots of ways to convey information. Reading strategies arise when the author and the reader have a certain mutual understanding concerning how the information is to be presented. The trick is to figure out the conventions of your genre. Humanities books are different from Science books, Science books are very different from scientific abstracts. I think I went somewhat backwards in that I earnestly read scientific abstracts on the internet before I really attempted the reading of scientific textbooks with adult earnestness. Humanities textbooks didn't come much later, with college. I was initially frustrated with the lack of brevity with which humanities were written - reading them in the science reading style doesn't work and will result in much information loss. I think that a humanities-style reading in the Sciences would probably result in excessive time usage, confusion, and memory overload. I believe that this is not because humanities and sciences are inherently different, but because the two genres have different conventions.

Your reading style will also be shaped by your goals in reading (and the goals of the majority of readers reading shape the reading conventions). For non-fiction, the primary distinction is whether you are reading to fill in known unknowns (looking for an answer to a question) or unknown unknowns (increasing general knowledge in an area without having any questions).

For science textbooks if the material is review (approximately, stuff that we've known about since before 1920) I just read it like a novel and skip the parts I already know. My mind will form the models of how things work on the fly as i read, and everything is assumed to be true unless uncertainly is stated. It helps to make little marks concerning where you are confused or perceive a gap, as well as noting the information you intend to commit to memory (if any).

Science textbooks for which the material is novel (stuff that's still uncertain) the *citations jump out of the page for me. The textbook will typically provide an extremely condensed review of the material in question. My mind will group concepts in terms of each experiment. Each experiment must be evaluated critically as evidence (What do the experimenters think they demonstrated, what do I think it means, etc) . This sort of textbook is a tool for eating tons of abstracts at once - the citations are the roadmaps which divide one concept from another.

For scientific papers, I begin by thoroughly read every word of the abstract. Do I know what all the words mean? Do I understand what's going on? If not, read the introduction - otherwise skim it or skip it altogether and go directly to methods. Form opinions about the validity / implications of the data. Briefly check whether my conclusions match those of the authors. If they match, I'm done. If they don't match, read the rest of the paper and figure out the reason for the difference of opinion.

My best strategy with Humanities textbooks thus far has been to read the section I'm interested in front to back, like a novel.

Do you write notes by hand, on a computer?

I don't think it matters. What does matter is whether you write the notes in the book, or outside of it. Notes in the book will call your attention to the area when you are reading that page. Notes outside of the book (and don't keep too many of these, or your notes will be a book) will direct you to areas in the book. The former is kind of like episodic memory - it will trigger when you go there. The latter is like working memory - limited in space but useful for managing multiple things at once.

Accordingly, I only use notes if I want to remind myself of something. The actual organization of the material itself happens non-verbally. If I need to commit a complex set of concepts to memory (usually in preperation for a test) I'll make a diagram or a drawing.

Do you wear noise-canceling headphones?

Earplugs are cheaper. I typically only block out other stimuli if I'm under time pressure or if the material is really boring and my attention keeps running away. But I think boredom is "System 1" way of telling "System 2" that you are wasting your time so there is no good reason to read something boring unless you've been assigned it for a class (in which case, if you aren't one of the lucky multitudes who possess the gift of extrinsic motivation , tell system 1 to shut up).

I do find that reducing background noise can somewhat reduce overall tension and stress.

How often do you decide not to finish a book?

I only ever finish novel-style books. These can be non-fiction or science, but they'll be specifically designed for the purpose of keeping the reader hooked. For the other type, you can't really speak of finishing something that isn't linearly read.

Edit: As a final note - for me (and I suspect for most people) the limited resource is not time, but willpower. Tedium is the #1 source of willpower leakage, with frustration coming in at #2. The above advice is what I do - if I were to attempt to give advice that universally applies to everyone who is similar enough to me that they read Lesswrong, I'd say "read in the manner which is most enjoyable". It doesn't matter if you lose time doing so. Following your interest levels will automatically optimize for information density and relevance (assuming you are reading for self-directed reasons).

When I am wearing my academic hat, my technique is to first gather an enormous, excessive amount of material, including every book, paper, file and website I can download or haul from a library and skim abstracts, tables of contents, and titles to get a map of the topic in my head. I may only really read one or two of these references in detail. I sometimes put high-value nuggets of information in Anki. One critical thing for me is that this process is highly active and I must be feeling energetic. Reading technical material is not a sedate, passive experience for me, and if I am bored, my interest and thus my retention drop to zero. Thus, it is essential that I be sufficiently curious about the topic at hand that my curiosity powers me through the process. For me this is a critical part of my process.

Reading something for 6 hours spread across 6 days will result in more insight than reading it for 12 hours straight. The better sleep you get the stronger this effect is.* So: do things in parallel instead of serially if possible and take care of your sleep.

* These are just guesses based on my personal experience.

This post of mine might be helpful to you.

How to Read a Book has a large section on reading nonfiction.

I read physics textbooks all the time, as well as some math. Right now I'm working through Group Theory and Physics. The best advice I have to give is to pick the right textbooks. I have it easy since I can just ask professors what books to read. I tend to read them very slowly (3-4 months for a good sized book) but I'm a busy person. I take notes by hand.

Read the table of contents, read the index, read through the citations, read the preface/forward/intro, possibly read the concluding chapter. Then and only then do I dip into the book in a few targeted places, and then and only then do I (sometimes) read the entire book.

The setting

I read at home, a small one room apartment. The most crucial thing about the setting for me is light. I have several bright lights that I have timed to turn on at about 4 am. I wake up to them, no need for stressful alarm clocks. I also try to keep things clean, because clutter is a major distraction.

Reading time

I wake up at 4 am, I eat and wash quickly, then study till I have to leave for work or university. I usually start by reviewing my anki cards. Studying in the morning is almost effortless for me, studying in the evening is a major pain. I have a tendency to feel depressed and fatigued after 4 pm.

Deciding what to read next

I use a program called ToDoList. I usually start a project based on what my university studies require, then divide it into subtopics(projects) and prioritize them (on a scale from 1-10) and estimate how much time each topic takes to learn and how much time I should use on them based on the priorities. The priorities are based on how much I think I will need the knowledge for my work.

I also gather a list of sources and usually start from the least effortful material e.g. lecture powerpoints and basic articles and then move to textbooks and more indepth articles if feel the need to do so. After the plan is ready, I can fully concentrate on studying the topics from most to least important. Knowing that I do things in the correct order takes out the stressful thoughts of not having the time to study everything.

The program allows me to do all this and also record how much time things take so I can adjust my estimates accordingly. Recording the time you actually work also helps to keep honest to yourself: for example the time you spend at the library isn't necessarily a good proxy for estimating how much you actually study.

I have no system for reading nonfiction that doesn't involve my profession, but plan to have one in the future.

Do you write notes by hand, on a computer?

Always on a computer. Typing is always faster than writing, and I have a tendency to lose physical notes. Also my penmanship sucks unless I go extra slow.

Organizing knowledge

For ankifying knowledge directly, I try to follow the 20 rules of formulating knowledge by the developer of supermemo, the guy who developed the algorithm also used in Anki. For heavily interconnected/conceptual knowledge I use Freeplane, a mindmapping software, before I try to ankify it.

Memory aids

Spaced repetition is indispensable for effective learning, I use Anki. I also use various mnemonic systems: mnemonic major, peg system, acronyms, acrostics etc.

Do you wear noise-canceling headphones?

Yes. They are very useful if I happen to study in public. For studying I usually listen to ambient electronic music or loops of pleasant noises. Acoustic and vocal music are very distracting for me, perhaps because of my musical background.

Do you skim texts?

I skim to filter out topics that I have already learned or are too complicated to be practically useful. Skimming is also useful if I search for a particular bit of info.

Do you reread texts?

I reread segments as I'm trying to process them, otherwise almost never. If I have to reread, I think I've done something wrong in the first place.

How often do you reread “foundational” texts, or texts that shifted your paradigm?

I don't reread full texts, unless I want to re-experience the pleasure of discovery or brilliant writing, and even that is very rare.

How often do you decide not to finish a book?

I usually don't read full texts, as there is significant overlap and unnecessary filler in them, so I'd say 90 % of the time. I probably finish about 20 % of the fiction I read.

I scrutinise the bookshelves of other people, and judge them ask them for the core thesis of books that are of interest. This lets me avoid books that aren't a good investment of my time.