To find your ideal customer, you need to qualify those who have the necessary characteristics and separate them from those who do not.

Here's a video I made on this topic:

https://www.youtube.com/watch?v=XU6JsRmc1-Q

You need to look at layers of qualification, because demographics are not enough.

Psychographics, or what's going on in the mind of your perfect buyer, is an effective qualification method. What problem or key problem situations are they in, what emotions are they feeling, that they badly want to get out of--that you can fix?

Making an avatar or listing characteristics is all well and good, but you must also confirm that your target market actually contains people like that. Many sellers start with one idea of their target, and then change it as it morphs into what's really there as they learn about those true characteristics over time. This process is work, and for faster results expertise on your side is quite helpful.