Consider the example of patching eyes for a corneal abrasion. Learning how to ask these questions is a skill, and also a habit for lifelong learning. An evidence-based approach requires that you systematically and exhaustively search the medical literature to identify all of the relevant evidence. Searching the literature effectively and efficiently is another skill for your EBM toolkit. Once you have found some articles that attempt to answer your clinical question, you have to appraise their validity.
Validity can be internal or external.
A study with good internal validity has used the right study design and appropriate methods to answer the question. External validity can be thought of as generalizability - the results can be generalized to your patients, practice, or community. Assessing validity is an important skill, and modules 2 - 5 in this Web course will help you develop it. Finally, you have to decide whether the results can be applied to your practice. We all operate within constraints imposed by economics, health systems, patient preferences, culture, and availability of resources.