I hold a master's degree in electrical engineering from an accredited uni [here in the US]. Until i was half way thru graduate school, i had NO idea how to study for an exam. My dad never finished 8th grade, and me mum finished high school, and then took a secretarial short course. That was the extent of my exposure at home to academia. NOBODY, all the way through my school and uni years explained how to be a student. Nearly all of my classmates were in the same boat, except for a very few, who seemed to get straight A's, without working at all. I found out by accident, that the closest competitor in the 'all A's' group had an IQ that was 17 points lower than mine. I was getting C's and D's, and she was getting all A's. Inexplicable!!
I finally figured out, in the middle of grad school, that while i was studying and learning lots of stuff, most of what i studied was NOT on the actual exam - so i was wasting most of my study time - i might as well have been playing video games. The technique i developed was to target the instructor's lecture. I kept track of how much time they spent on each topic, and how much work they did - just talking about it, drawing on the board, prepared handouts, viewgraphs with an overhead projector. Each of these was more work, so i would assign a 'work factor' number. Just talking was a 1 to a 3 (for example). Drawing was a 4 to a 6. So if the instructor spent 3 minutes talking about it, and then 6 minutes drawing (medium complexity drawing), i would multiply the 3 minutes by 2 (medium complexity talk), and then add 6 minutes times 5 (medium complexity drawing. The result was 36 for this lecture section. I would add up the results for each time that particular topic was mentioned to get the 'total score' for that topic. I then ranked the topics in decreasing order - from highest to lowest.
The problems involved in these topics would take enough time to solve, that the average student could not do more than 4 or 5 in one hour - which was the time normally allocated for an average exam. I would take the top 7 or 8 topics in my ranking, and make up a problem for each one - trying to include everything that i'd seen in those types of problems in class and in the book. I then made sure that i could solve each of these problems without "breaking a sweat". The first time i did this, i hit the guy 100%. I had every problem on the actual exam on my "practice" exam. It took me 12 minutes to do the hour exam - plus another 5 minutes to check all my work 3 times. I used the same technique for the rest of my remaining graduate school courses (5 of them). The worst i ever did was hitting 70% of the exam questions. Several times i hit 100% again. On average, it took me about 15 minutes to do the 1 hour exam. Now, years later, i understand how my classmates in high school were getting A's whilst never seeming to study. Of course, they would never have told me what they were doing, because they didn't want me to start doing it too. Best of luck!!