The literature search is a constantly evolving process. After you identify a topic, create a search question, and formulate a search strategy, it is time to start appraising the quality of the articles your search has brought back.
Evaluate your results to see if your search strategies are bringing back too few articles, too many articles, or if you are in the "perfect" situation where you have a manageable number of relevant articles being retrieved.
For keyword searches, this would be a good time to play with new terms you may have seen as you are scanning the literature: can you incorporate any into an advanced search?
For an advanced search, this may be a good time to start playing with a different operator. If you need to narrow your results, are there two or three words you can enclose in quotation marks? If you are concerned with widening your results, can you truncate one of your words?
At this point you should have some promising articles that fall within the parameters of your search, and it is time to narrow them down using your appraisal skills. Did you establish inclusion/exclusion criteria? Time to apply them!
Questions to Consider:
Keep in mind you can have more questions, or less, than the above when analyzing an article. This list is meant to jump start your appraisal skills. At this point, you want to check that you have a quality article but also that the quality article is relevant to your research or clinical question.