I think "stick to the old way you studied" is pretty poor advice. Generally, in undergrad there is plenty of time to cover ALL the class material well. In undergrad, I always went into a test knowing I was prepared and had reviewed each lecture/lesson many times. In PT school, I never had time to review all the material in anatomy to that depth. Often, I went into anatomy tests knowing I only had enough time to glance through 1-2 lectures. I never had that sense of being prepared and feeling like I knew what I needed to know going into the test.
So...step 1) give up the idea of trying to learn everything to the depth you want to learn them. Instead, agree that you need to learn the important stuff well and then whatever else you have time for. 2) don't assume that your old ways of studying were efficient...be open to trying new ways. I had to completely redo my approach and now I spend a lot of time working with my classmates or classmates under me trying to help them do the same. 3) Learn to differentiate between "passive" and "active" studying. In my life, I don't have a spare second....so I don't do ANY passive studying. Some people may be able to get in some passive studying, but the large portion of your time should be active.
Passive studying: reading the book, reading lecture, looking a picture, re watching a lecture, listening to pod cast lecture
Active studying: demonstrating recall in different formats (verbal, written), quizzing with classmates, flow charts, flashcards
You have to force yourself to be efficient with time. For example, for every hour of lecture I had, I gave myself 2 hours MAX to consolidate/condense. And that's it. When the 2 hours are up, I had to be done and my lecture should be reduced to a much smaller and focused bite with only most important stuff in it. This forces you to quickly make decisions on what is the important material and what is tiny material and then you move on. My preferred method was to take a 1 hour block of lecture and spend 1-2 hours (usually just 1 hour) making a flashcard deck for the lecture. I really love the Anki program. Then I never went back to that lecture again. I would only use my flashcards from there out which puts you into recall mode. When using flashcard, make yourself say the answer out loud too....bringing in that verbal component takes it up another level.
Other classmates who did well would consolidate lectures into charts or pictures. I used whiteboard extensively and would force myself to reteach a segment of the lecture without reference and then check my work after.
I noticed that classmates who didn't do so well spent hours and hours reading the textbook or rematching lectures or watching videos or re reading lectures (all passive!). And sadly, they usually put in way more hours doing that.