You are probably solving a problem, right? Ask yourself how would you go about finding the solution to such problem and go there. "There" will be some blogs, community websites etc where you can add comments whenever a relevant question comes up for discussion. This worked for me.
What didn't work: approaching any kind of famous blogger (zero responce), google ads (huge money drain).
What didn't work: approaching any kind of famous blogger (zero responce), google ads (huge money drain).