To search for evidence based information, you first need to develop a well formed clinical question. It is recommended that you use the PICO concept to help you do this. 
Pico stands for:
Patient, Population or Problem
What are the characteristics of the patient or population?
What is the condition or disease you are interested in?
Intervention or exposure
What do you want to do with this patient (e.g. treat, diagnose, observe)?
Comparison
What is the alternative to the intervention (e.g. placebo, different drug, surgery)?
Outcome
What are the relevant outcomes (e.g. morbidity, death, complications)?
See an example in the right hand box.
Here are some helpful documents from the Purdue University Libraries Guide on Evidence Based Practice
Once you have established your focused clinical question, you then need to convert it into an effective search strategy. Use this PICO worksheet to assist in the process. This involves identifying: