As a person that owns a market validation company, I see people coming with an idea that has no audience at all. They think that they guessed that there is a market, they asked friends and family to seek approval, but when they built a product it turned out no one wanted to use it.
Sure, try to guess your market, but validate it as well. Otherwise, you might run into troubles!
There are many ways of validating the market, from picking up a phone, to giving out flyers or doing surveys.