Registering for classes can be overwhelming but there is a way that you can create your perfect schedule with a balanced workload and class time per day.
Make a list of about 10 or so courses you need to take for either your major, general requirements or classes that you are just interested in taking.
Step2
never take a class with a bad ratemyprofessor.com rating unless absolutely necessary
Go on ratemyprofessor.com and look up every professor and make notes next to each. Not all professors will be on ratemyprofessor.com that doesn't mean that they are bad it just means no one's has posted any ratings for them. Start eliminating courses which have poor rating's unless you absolutely need to take that class this particular semester. A lot of courses can have more then one professor and rotate from semester to semester, when possible wait until their is a better professor.
Step3
See if there are any classes that you must take because either that's the only semester they're offered or that's the semester that the "good" professor teaches it.
Step4
From there pick a class that you need to take and you know it's going to be your most challenging.
Step5
Draw out a mock schedule. This way you can decide between the final classes by seeing which one's time's work better. Also, try not overload to many classes in one day you want to create a semi-balanced schedule.
Step6
Have backups because desirable classes fill up quickly. If you really want to take a class you have to religiously check your school's timetable for an opening, students are constantly switching around their schedule.
Tips & Warnings
you can always search your school's website for past syllabi to see if you can handle the work load or are interested in the subject matter
when in doubt ask around for easy and/or enjoyable classes that older student's recommend
some semester's are going to be harder then others and sometimes there isn't anything you can do about it