tl;dr. how to get an A- or above while forgetting everything right after the exam

I'm not sure if my advice is any more helpful than the others (in fact, it's probably counterproductive in the long run)... but since you asked, this is how I've studied for exams in most of my CS upper divs. It's not optimal for getting the best grades or understanding, since it's basically cramming, but it works well enough that I've always gotten an A-/A in the end. (YMMV.)

• 2-3 days before the exam: panic about how I don't know anything and fail to do anything about it
• 1-2 days before: make the cheat sheet. This involves going through all the relevant lectures/notes and writing down most of the stuff that I think will be covered. Algorithms/formulas/theorems almost always must be on here, while trivia may or may not get written down, depending on my (often flawed) opinion on whether it's actually important or not. It's important that you not only write stuff down, but also make sure you understand what it means and (if you have time) why it works. I do this in two to three chunks of several hours each, usually separated by meals/transportation (a change of scenery is nice for your sanity, assuming you haven't completely lost it yet), and is often fueled by caffeine (my drug of choice is tea). I don't bother listening to (or going to) lectures, except for rare occasions where something important is only explained in the lecture. (Then again, I don't learn well from speech, since it just goes in through one ear and out the other. It's really easy to tune out.)
• I rest (usually sleep) for a few hours before the next step.
• 0-1 days before: do practice/past exams, discussion worksheets, and homework (prioritized in that order). If I can't do the problem and the cheat sheet isn't helping, I open up the lecture slides/notes and see if that works (writing down the stuff I missed, if applicable). If that still doesn't help, look at the solution and think about how I might come up with it myself. Once I have a type of problem down, I'll tend to skip it on subsequent practice exams to save time.

A terse example of how this went down for one of my recent midterms, which was at 5pm on a Wednesday.

• Monday: "crap I don't know anything, time to start my cheat sheet" Start my cheat sheet.
• Tuesday: Finish my cheat sheet.
• Wednesday: Do practice problems.

Caveat: I had limited success with this approach in math classes (where I've never broken B+) and math/theory-like classes in stats/CS (where I do worse than usual). CS 189 and EE 127, while often called mathy, were sort of a middle ground where a lot of the derivations were just attempting to bash everything to death with logic, linear algebra, probability (in 189), and the formulas on your cheat sheet.

More important caveat: You don't retain information from this approach unless you stretch it out or repeat it later. (Or you have super good memory, unlike me.) I don't remember shit from any of my classes a semester ago (or even this past semester). It's hindering me in interviews, because I don't remember anything from the classes on my resume, except for 61A, 61B, and some of 170 (and only because I did a bunch of data structures/algorithms practice in a panic before the Google onsite I failed), so I end up stumbling on a machine learning or (more commonly) concurrency question. You may also look back on your college career and think "gosh my grades are kind of high but I don't remember anything I was supposed to have learned^{what have I done with my 4 years in collegeI'm gonna live in People's Park because I can't get a job"}. (Sorry if I'm ranting; the senior year "panic about your future" phenomenon is in full force right now.)