Most important in my experience are the terms that you choose for a search. Sometimes it helps to think about how most people would phrase a question.

Often results can be too broad ... so use them to choose more specific terms to add to your query to 'focus in' on the result you need. (E.g. adding years (even specific dates) can add focus -and quality- to your results.)

It helps to keep a growing list of bookmarks for high-quality 'specialist' sites with -a lot- of content.