This may sound smart, but it is not intended to be.
Do you know how to study? (I have found many people who come to EMS do not)
First, read the text for the big picture. After you understand it, then go back for the details.
You cannot memorize medicine. It is too large. You must understand concepts. Many students I have seen have never taken a class out of highschool before. Sometimes you must consult other published sources and the teachers don't just tell you the answers on the test.
Don't skip over things thinking you know them. You don't. I made that mistake many times myself and always paid dearly for it in lost time going back over what I thought I knew several times trying to unlearn what I thought was right and learn what really is.
Learn one, do one, teach one. After you learn something, explain it to somebody else. Significant others, younger or older family members, etc. If you can explain it and answer questions about it, you know it. If you can only identify buzzwords when you see them, you do not.
Reading...
Do not try to power through 100 pages because you can. When you read something, take a minute or so to think about what it is you read. How does it fit into what you know already? How does it connect with other facts in the chapter.
Test taking.
When taking a test, take your time. Read the question. Decide what it is asking. Then look at the answers... All of them.
Medical tests, especially the higher you go like to ask what is "more correct."
Take some time, think about usually the 2 or 3 distractors that could all be the right answer. Don't pick the first answer that looks right.
Read the question and answer you chose as a sentence. Does it sound right? If it doesn't, then it is probably not the answer.
Beware "what comes next" which means something which is usually a distractor is already done.
Do the questions you know first. Then come back for the ones that you are going to think about.
Don't worry about how many you need to get right. Make sure you get the question you are working on right.
Instructors:
Some are great. Some suck. Some know how to write a test. Some do not. In academia 75% of the class should fall into the passing range. If they don't. The problem is not the student.
Many EMS instructors have never had any formal teaching training or academic experience. Don't be taken in by war stories and think that is a good teacher. If you teacher is poor, you have to make up for it by studying extra.