Writing courses are expensive and time consuming, and it is hard to know what you are getting into before you sign up. I've taken a number of online courses through the UCLA Extension Writers Program and thought it might be helpful to share my experiences here.
Part 1: The Benefits
Part 2: The Downsides
Part 3: Choosing a Writing Class
Taking a writing class is a gamble. The quality of the class depends entirely on how good the teacher and the other classmates are, and there is no way to determine this before the class starts. Since many of these classes have non-refundable fees, the more information you can get about the class beforehand the better off you are.
First, make sure the class is actually appropriate for your goals. Many class descriptions are vague or misleading, and you might have to read between the lines to be sure the class fits your interests. I saw one class about heroic archetypes that I thought would be perfect for me - and then at the end of the description I realized the class was for memoir writers!
Even if the class sounds good, you don't know if the assignments or lectures will be helpful. Try to find a sample syllabus if you can - I know many of the UCLA Extension Writers Program classes are now posting their syllabuses (syllabi?) online before the class starts. Or you could try emailing the teacher and asking for more information about the class and the assignments before signing up.
Since the teacher makes such a huge difference in the quality of the class you should research them as much as possible. First of all, don't take a writing class by someone who isn't published or working in the publishing industry. This should be obvious, but many classes are taught by people who might have less writing experience than you do!
Once you've found a teacher who has some verifiable writing or publishing experience, google them and see what you can find. What kind of reviews does their book have? Does it sound interesting to you, and can you read any sample pages? What is their website like? Do you have a good feeling about them as a person and as a writer? Trust your instincts - if you see warning signs about the person don't take the class.
Unfortunately, there is little you can do to screen your classmates before you start the class. Classes that focus on a specific genre will weed out some of the genre snobs, and classes that require submissions to enroll will prevent some of the newbies from signing up. However, you will still find some weird and negative people in any class you take. Just try to be the best writer and classmate you can be, and concentrate on getting the most out of the classes you take.
Please let me know if you have any questions, and feel free to share your own writing class experiences!