How do you find out about related projects or businesses?

[Mehdi Samadi]

When you come up with a great idea, you probably immediately wonder "Has anybody else already done this?  What similar things have already been done?"  How do you answer these kind of questions? Which tools do you use?  How much time do you typically spend doing this (per idea)? What capabilities would you expect from a tool offering to make this process _significantly_ easier and faster for you? I appreciate your help :)