Look for glossaries or dictionaries. Some sites will provide a definition when you hover over a word, others have a specific sub-page, or a section at the bottom of a page.
Look for a site map, headings, subheadings or breadcrumbs.
If an advanced search option is not available, experiment in the standard search box with limiters, Boolean logic (AND, OR or NOT) quotation marks, or common keyboard shortcuts.
For example, Google search has replaced the use of the word AND with a plus sign (+), the word NOT with a minus sign (-)
Want more tips for searching Google?
Think about your question from a broader perspective. For example, who are the key decision makers related to a particular policy? What agency is responsible for the field? Is more than one agency involved?
Try creating a keyword map
Add a limiter to narrow your focus.
Focus on a specific population or stakeholder
Government documents use a specific style of citation which can be difficult to interpret.
Check out this straightforward explanation by Government Librarian Jen Kirk at Utah State University for help.