There are many strategies that you may employ when looking for information in a database. When starting your search, it is important to plan out your search strategy in advance, and follow these 4 important steps to insure that you receive the results that you are looking for.
1. Define your topic (write a few sentences that explain what you are looking for)
2. Choose keywords (select keywords from your sentences)
3. Group like keywords together
4. Decide how groups of keywords are related.
Here's a helpful video on choosing your keywords to build an effective search strategy from McMaster University.