One of the things I factor in the most isn't even the product itself, but the product's landing page. A lot of those CB products have Ugly Ass landing pages (emphasized by capital letters?), and I can see why they don't convert worth a shit. Not even just ugly, but very spammy looking. Like you're gonna get malware from clicking on the page or something...Sometimes it doesn't matter how well you pre-sell it, they hit that page and are like WTF am I looking at? I try to think of it from a non IM person's perspective and determine "would have even considered buying something from this page?". It's obviously hard to put yourself in the shoes of someone not familiar with what you've had experience in, but at the very least you can roughly judge it. Often our target audience for a product will primarily be people that we can't relate to hardly at all, and some marketers are just better than others at getting in the mindset of their customer, and consequently better at turning a "product" into something that the audience truly wants and even thinks they need.
On the flip side, surprisingly, some of those "ugly" pages actually work very well with a specific audience. So rather than the 'spray n pray' method, you really have to find where your target audience is and get them to that page, instead of crossing your fingers and hoping someone you sent is your target audience.
CB has always been pretty hit or miss for me, to the point that I was convinced they weren't actually tracking all my conversions at one time lol...Of course you could sell air with the right sales pitch, but in my experience many CB products are just too low of quality to have been able to make sales at all without the driving force behind them: thousands of internet marketers promoting them in as many possible different ways as you can think of, and then a few more. These days if it's not a product I could confidently sell to people in real life, I avoid it - so basically I don't fuck with CB anymore, unless it's something I can promote on autopilot without spending any time on it from a day to day basis or a product I truly think brings value to a customer.
"When you can make more off CPM from your traffic than an affiliate program, it's time to switch things up one way or another."