Learn how to think critcally about the information you encounter, both in print and online. Become familiar with strategies to evaluate sources based upon these criteria: authority, accuracy, currency, relavance, and objectivity.
What are the best sources of information? That depends upon your research.
Always check with your instructor for guidance.
If you're ever in doubt about whether or not to use a particular source, ask yourself if you would be comfortable including the site in an academic paper.
Keep in mind that while some sources are fine for simple general inquiry, they may not be suitable for academic purposes.
Would the sources you used lend YOU credibility?