Because schools vary so much this is a really good topic to ask about on the school parent’s facebook page which you can usually find and join after your child commits to the school. Also encourage your kid to ask on any social media groups they join that include upperclassman. The best strategy is one that takes into account the particular situation at the school.
For some people maintaining that GPA is necessary to hold a scholarship. It is wise to give this some thought and planning.
My oldest is at a school where it is hard to get into all the classes you want/need. Every semester she registers as best she can and joins the waitlist for what she really wants. The first week of school she is attending the classes she is registered for as well as the waitlist ones so that if she gets in she isn’t behind. It always works out okay but it is a bit stressful until it does.
Most students can tell by the first class and a careful read of the syllabus if the class is a good fit for them.