Every law student randomly gets assigned either an “A”, “B”, “C”, or “D” pass each semester. When you pick classes you should think about what letter pass you have for the current semester, but also check what letter passes you have for your remaining semesters.
You should think strategically depending on what pass you have. “A” and “B” passes allow you to select classes first so you should always use your “A” or “B” pass to enroll in courses that fill up quickly (many seminars for example, or other small-enrollment courses). It’s a good idea to plan to take a seminar and write your SAW paper when you have an “A” pass and a stronger likelihood of being able to enroll in a seminar.
If you have a “C” or “D” pass, you should definitely have back-up choices in case you can’t get your first choice when you enroll. You could try signing up for courses with large enrollment capacity or courses that are offered every semester. It’s very hard to get into a seminar if you have a “C” or “D” pass since seminars only take a small number of students and they fill up so quickly.