Margen
Out of the last page you read, pick the paragraph that actually matters to you and say it out loud. One per page, not the whole page. That spoken paragraph is later recognised about ten points better than the one you read in silence: ten more answers in every hundred, which is not the same thing as a ten per cent improvement.
That is the whole method. Colin MacLeod's team at the University of Waterloo has been measuring since 2010 what they named the production effect: in memory tests, the words and sentences a subject has read aloud are remembered better than the ones read without pronouncing them. No materials, no app. Just saying it.
But there is a catch, and it is probably the reason it has never worked for you.
The effect lives on contrast. In the experiments, the subject reads a few items aloud and the rest inside their head, and what gets measured is the difference between those two halves. When the WHOLE list is read aloud, those ten points fall to practically nothing. Anyone who sits down to recite the entire chapter ends up with a dry throat and the same retention as reading normally, and takes twice as long doing it.
So the practical instruction has considerably more small print than "read out loud". Here it is in full:
Read the text straight through at your own pace, without pronouncing anything. At the end of each page, decide what the one thing is that you would have to be able to repeat if somebody asked you tomorrow: a definition, a figure with its unit, the name of whoever did something, the step you always forget. Mark that fragment and no other.
Then say it out loud, yourself, in your own voice and at speaking speed, looking at the page. Loud enough to be heard. Whispering and mouthing the words without sound also work, but less well, and a recording of your voice or somebody else reading it to you works less well still: what counts is that you produce it.
And add the gesture that multiplies all of the above at no cost: after saying it while looking at the text, look away and say it again from memory. The first pass is production; the second is retrieval, which is the other mechanism with solid evidence behind it.
Three warnings so you do not ruin it. If the fragment you picked runs past five or six lines, you are no longer picking. If a reciting voice creeps in, bring it down to the voice you use to tell somebody something, because what gets remembered is the act of speaking and not the intonation. And if you are on a train or in a library, properly mouthing the words leaves you most of the effect and does not leave you exposed.
Tonight, with whatever you have in hand — a manual, a contract, an exam topic, the instructions for the new oven — do only this: one page, one paragraph, twice out loud, the second time without looking.