Q&A: Graduate School after online classes: What's the difference?
A: Many of the key elements in going from undergraduate to graduate school are the same. You still need to find (and fund!) a program, take the GREs, write a letter of application /intent, and so on.
A few key points differ, though. Some should be pretty obvious: in the traditional classroom, you'll have more opportunities to speak up in class, give presentations, etc. Unless you seek it out, you'll have less public speaking experience when you graduate than someone who attends a traditional school. When it comes time for the interview, you may come up short.
The main differences relate to the interpersonal contacts, especially those that blur over into professional activities. At a traditional school, ambitious students might stay after class to discuss the material, or stop by office hours (without a complaint!). Seeing potential, professors might ask them to be research assistants, tutor writing, edit student publications, or help in a lab. These extended experiences outside the classroom, where the students exercised more responsibility, would deepen professors' understanding of their students. The more professors know about you, the better they can help you choose a program -- and the more vivid and persuasive their letters of recommendation will be. Likewise, the more you know about your discipline, the better decisions you'll make about graduate school.
Online, you lack many of these chances for exposure. In fact, depending on how your online school schedules, you might not even be able to take a second class with a professor you really like. Therefore, to prepare for graduate school, you'll need to actively seek out networking and professional preparation opportunities on your own.