1. Have a good PICO research question/topic 
2. Create a keyword list - modify it as you search 
3. Identify places to search 
4. Search using Boolean operators 
5. Use database features like filters and subject headings 
6. Use truncation (with caution!) 
7. Search, modify search, and search again 

Using Boolean operators you can take the core concepts from your keyword list and string them together. 

A typical search can look like: 

(dance therapy) AND (adolescent)

This will bring me back all articles that contain all three terms. But if I want to expand my pool (and get other relevant articles), I can add additional search terms or keywords so my search string looks like: 

(dance therapy) AND (adolescent OR children) AND (stress OR anxiety)

Using AND/OR together will both broaden the results you get (OR) but make them revelant to your topic (AND).