Customer discovery by far. There are processes to ask questions and have conversations with potential customers. I'd say that if folks spend more time just doing that process of learning their market and going through the iterations about having conversations even before putting a website up. Even before writing a line of code. There are some great resources out there. Such as worksheets and canvases to fill out and that kind of stuff. That's where I would suggest starting. Spend the time there, make a gel and then move on to the really heavy lifting.