Start with a general topic/broad keyword(s) then narrow as you build.
- Use a Thesaurus to find alternate terms
- Brainstorm for keywords that are most important in defining your topic
- Break your topic into categories using questions
- Who? [broad topic] American Space Exploration
- What? [specific topic/group] Manned Space Missions
- Where? [geographically] Moon Exploration
- When? [time period] 1960's
- Why? [why did this action take place/why does it matter] Quest to leave Earth
- How? [how was this achieved/not achieved?] Rocket to the Moon: Space Exploration