Minimize distractions, including online distractions. Constantly viewing your favorite bookmarked sites is a temptation that will send you off track. Temporarily hide your bookmarks or use another web browser for studying purposes. Another option is to study using a library computer, because you simultaneously minimize real-world and online interruptions.
Cross-check information for accuracy. If you learn something, confirm what you've learned by visiting other websites. Unlike scholarly textbooks, most online websites don't use primary, authoritative sources to verify information. University and government websites are some of the safest places to find reliable information.
Take breaks to reduce stress and replenish energy. Studying online for long periods contributes to eyestrain and headaches, and this reduces the effectiveness of your study session. Do something relaxing or fun, have a snack and think about things other than your studies.
Take notes on important information. Writing provides an effective means of remembering material. Try using a mind map, a diagram where you categorize ideas by how they relate to a central idea. Find mind-mapping programs online or on the iPhone, or draw one by hand.
Make use of online tools. Sites like Sparknotes provide summaries and quizzes on a variety of subjects, and Flashcard Exchange allows you to make free online flashcards for review.