Well, first of all, I guess it helps to be more specific about your goals and tasks. Students tend to wander around with their thoughts, being romantic about the idea of studying any subject and thinking about how they ideally could study.
But the simple truth is: You have to work on what you have to work on. And your goal probably will simply be "Understand every detail of the course." Eventually "learning and understanding math" will take care of its own.
A lot of this work includes work, that appears as "unnecessary" or "uncomfortable" for the student. But this work is actually crucial to learn for a student. For example, contacting your lecturer, asking questions about details and willing to work on details for a longer period of time. Also willing to ask a second time about the detail you have not understood, when he/she explained it the first time.
If you think about it twice, you will realise, that the best way to prepare for your course, would be to find out, who your lecturer is and what this course is about in more detail. A lot of professors taught the same course some time ago and have scripts and textbooks available on their homepage for this specific course. Find out about that and study this textbook. If you cannot find this textbook, ask yourself again, what obvious task has to be done otherwise and how you can solve it. Probably: Ask your lecturer, if he has already a script for the course or a textbook, he can recommend. And actually write this mail. Tasks that feel uncomfortable to be done, sometimes can have the most impact on solving an issue. This does not mean that you should not use any other books. It only means you should use books in order to understand the topics and contents of the course.
Otherwise this can lead to a typical frustation a lot of math students experience: They will try to work around the "uncomfortable tasks" by spending a lot of time on "somehow understand", but will have an even harder time studying for the actual course. They spend too much time on trying to learn from books or thinking about how things should be, instead of facing and attack the next step, they should be actually working on. Courses are designed to teach you the steps that are necessary to be done. Instead of thinking about, if the course is done right way, you should rather try to think about, how you can deal with it the right way.
And lately about studying a math text for a course. It is again quite simple. Read it from beginning to the end. If there appear details, you do not understand: Spend time to make a good request for that, for example here on stackexchange: Write down the problem properly, write down what you already have tried to solve the problem, write down your question properly. Often, just by figuring out, what you want to ask, you might find an answer to your question yourself, because you specify about what you want to find out.