It will depend on the course (I do psychology) and on the individual, as everyone is different.
For me I have different techniques depending on the type of exam
For multiple choice exams I have a pretty good memory, so I go through every lecture online and write everything out in my own words on flash cards or in a small notebook a few weeks before exam season. I then read this every couple of days, and do a bit of testing myself at the same time. The week before the exam I mostly focus on rewriting my notes over and over, and doing any practice papers that lecturers have handed out or testing friends etc probably doing about an 1 hour everyday for each exam.
I generally speaking get marks at least in the 80's but mostly in the 90's for these exams.
For essays where I already know the title I do my research like any essay, and then compose a very detailed plan and remember that. In the past I would write an essay before the exam but experience has shown me that doesn't work for me. I prefer to just let my writing flow at the time.
I also tend to remember about 15 references (name and date only) for each essay. I normally remember them in order, and repeat them over and over in my head until the exam starts, and then I scribble them down at the top of the page.
I normally get high 2.1's or low 1st's
Essay exams with an unknown title are the hardest but for that I tend to focus on collecting enough references that could be used to answer numerous different questions depending on how and when they are used.
I tend to get 2.1's