For me, I'd start marketing a lot earlier. When we started building TurtlePic, I kept telling myself, "We'll start marketing once the product is ready." The problem is, I don't think a product is ever really finished. Every week I find something that could be improved or another feature that would make the product better. If I waited until it felt "complete," I'd probably still be waiting. What surprised me was how much harder marketing turned out to be. With developmen...