Professor John Bronsteen advises on
"Curriculum Planning"

I advise you to choose courses by the professor rather than by the subject matter. A good teacher can make any subject fascinating and valuable, whereas a bad one can make any subject a waste of your time. Three of the best courses I took as a law student were Civil Procedure, Trusts and Estates, and Advanced Legal Writing - none of which are typically regarded as particularly interesting, and none of which I would have expected to like. But the professors were riveting and effective (in three entirely different ways), so I learned and remembered much more of the material than I did in my other courses, and my life was positively influenced as a result. I ended up publishing a book about legal writing and several academic articles about civil procedure.

How do you know which teachers will be good, or which ones you'll most enjoy and learn from? One way is personal experience. By the time you choose courses, you'll already have taken a bunch of required courses. If you liked one course by a specific professor, chances are good that you'll like the next one as well. Another way is to ask your fellow students, and perhaps also the school's administrators, which teachers they'd recommend. The more people you ask, the more reliable the advice will be.

It can be hard to know in advance which subjects will be valuable to you, or which areas of law you might end up practicing. Rather than trying to guess, you're better served by focusing on something that you and your fellow students can judge easily - which people you learn the most from and most enjoy learning from (I think that those two things go hand in hand).

Some students take courses because the subject matter will be tested on the bar examination, but I view that as a mistake. I'm aware of no evidence that taking any course or set of courses in law school improves a student's performance on the bar. The bar preparation courses such as Barbri that you can enroll in and take during the summer after graduation will teach you all you need to know. An enormously high percentage of people pass the bar, especially if they take one of those bar preparation courses and study seriously. When people fail the bar, it might be due to problems in test-taking skills, or insufficient studying, or several other factors, but I believe it's virtually never due to their course selection in law school.

In short, I recommend that you choose the courses you want to take - the ones you think you'll like the most. And the most reliable predictor by far of how much you'll like a course is how much you like the way it's taught. So find the people whose teaching you prefer, and take as many of their courses as are offered.