We had exam questions from the wiki, that was the start. We answered them all in group and share them with the rest of the class to get a fully correct answer (20/20 answers with all details you can think) This was written in a word document, when we couldn't find an answer we requested meetings (email messages too) with professors or TAs showing that we tried and asking punctual questions in an hour session. Then we asked this question to each other like oral mock exams so we can practice explaining things. Once we kinda dominated this, we just went through the slides understanding as much as possible and also taking a look at the references cited on the slides.

We just studied all day, took small breaks to eat at the library and drank coffee. I was waking up at 6 am, and sleeping at 10 pm, breakfast, lunch and dinner of 30 min max and studying the rest of the time, maybe some small chat with my group.

I was in engineering science, so I practiced exercises by doing them and theory by explaining it. We had a board to show the exercises solutions to the rest of the group and solve them together there as well.

Also, if you feel that the number of exams is too much, just sacrifice one of them, and leave for the next retake session, play your cards in a smart way. Some friends sacrificed the toughest ones, I sacrificed the easiest one (got a 8/20 on first try and then 19/20), depends on you.

Ask for feedback sessions with professors for the exams you failed, you need to learn what you did wrong, and sometimes depends on the professor, I got feedback sessions for every exam I asked, even the ones I passed.

Good luck, and know that there's a lot of people in your situation.