I like to use the same techniques as developing a topic sentence, for developing a search strategy.

Start with your topic sentence.  I am researching foster care and in patient facilities.  I need to look at legislation, legislative histories, court cases at the state federal levels.

Next break it down.  What are other words that can be used?

foster care

in patient

legislation or law

literature review

Connect the terms using the following connectors  foster care and in patient and (youth or young adult or teen*) and (legislation or laws)

and : narrows your results.  All words must be in the results  foster care and children

or : broadens your results.  Any of the words must be in your results. youth or young adult or teen

not : excludes words.  

() : allows you to combine it all together.  

* picks up the various ends to a root word.  teen*   will result in teen, teens, teenagers