I have done a lot of mistakes while trying to grow a product. [You will see my list down below]
From knowing nothing about product growth, to too many expensive experiments, I have come a long way and I continue to learn. I am curious about what are some of the methods/channels, that you know through your experiences, that just don't work at all. (This of course totally depends on the kind of products as well)
P.S: You should pick up Traction by Gabriel Weinberg and Justin Mares. It's a good starting point to identify right channels.