By asking yourself these questions before you start your research you are able to plan out your most effective search strategy.
Currency - Is the information current and up-to-date?
Relevance - Does this source contain a lot of useful information, or is it too basic, complex or unrelated to my topic?
Authority - Who is the author/publisher of this source and what are their qualifications? Are they an expert on this topic?
Accuracy - Is information supported by evidence? How has it been reviewed or fact-checked?
Purpose - What is the purpose of this source - to inform, entertain, persuade, sell, etc.? Is this purpose clear or is the author trying to hide something?