The first thing is to decide what you need to know.
Try and think of some words or phrases that sum up what you are interested in.
For example if you want to know more about children in Tudor times think of as many things as you can to do with children.
We eggheads call these words keywords
You can use these keywords to search for the information you need
A good tip is to write the question in the middle of a page and all round it write words that might relate to it.