Evaluating the evidence for quality is a critical component of evidence based practice. Consider where the evidence sits in the evidence hierarchy and use the strongest evidence possible. If there is not any evidence available at the top levels, you may need to drop lower in the hierarchy. Be critical
Be judicious in your use of free reference material on the internet. For example Wikipedia is a collaborative online encyclopedia to which anyone can contribute. Information in Wikipedia is not necessarily accurate nor authoritative, however it can be a starting point to identify keywords which relate to your research topic.
Centre for Evidence-Based Medicine appraisal sheets/tools - guide sheets for critical appraisal of random control trials, systematic reviews, etc.