I used to be rather casual about choosing countries for trading offers: I launched a couple of campaigns where it was cheaper and waited for results. At some point, I realized it was like launching a plane without a map—you might take off beautifully, but you're not guaranteed to land well. I came across a piece that explained the main topic in simple terms—comparing geographic locations, traffic, and conversions. After that, I started choosing countries consciously, and the ROI finally started to please me.