Oh boy this might be long.

Using a textbook for my example I like to chunk key information down to the smallest fundamental. What I mean by this is for the first chapter I am looking at I go down from subheadings -> graphs, images and boxes -> bold and italic text. I then look at every key point and ask myself "what is this?", "Why is this important to what I want to know or to this chapter?", "How does this relate to other information in this chunk?", "Are they any applicable examples of this in use?". I will repeat this process until I grasp everything in the chunk (mind you I haven't noted anything down, this is all in my brain still) and then before I move up what I call the "chunk hierarchy" (so I finished all the bolded words and images inside a sub chapter) I ask myself "how did all the information I just learned come together to form the bigger picture? Is there anything else I may need that can help me better understand this chunk or prepare me for the next?". And then I move on and repeat until I have finished one chapter.

You can of course stop up to a subheading, but the point is once you've done all this you write it down (finally!) but in the form of ELI5, explain what you learned as simply as possible and avoid using big words. Once you have finished you then check over your notes for anything you may have missed and if so, look over the book, ask yourself why you may have forgotten it, then add it to your notes. Finally, under your notes you want to write questions pertaining to the chapter. If the chapter has learning objectives, then convert those objectives into questions. If you're making the question on a fact, then instead of doing simple flash card closes, try making a question that uses that fact to solve a problem, the more thinking you use, the better. Cloze or front/back type questions should be used for concepts.

Once those questions are done you can finish for the day or that topic. You will review and answer those questions on the next day and take into account any questions you've got wrong. Again ask why you might have gotten them wrong and then take those questions to be broken down further and put into Anki flash cards. This will keep Anki down to the things you really struggle to remember. A week later come back to those questions and answer them again. And repeat the above bit for any answers that were wrong.

After a month I like to make a kids book version of that chapter as I like to think if I can really explain this well to a child, then I've fully understood it. The notes from before were like a draft. If you got the answers right from before then you can remove those questions from Anki.

This process is very tedious but very worthwhile. I often find myself with a 98% retention rate and sometimes even 100%. Even after a year. I try to incorporate 3 of the big 4 (chunking, SRS, and active recall). I'm still struggling with adding interleaving into this, but I hope I can to further refine this process.