My first startup failed because I had no idea what I was doing. I started an online vacation rental site, similar to vacationrentals.com vrbo, homeaway etc... I was getting traction and had people list their rentals on my site but I failed to collect any revenue. The thought was, build it, offer it for free to grow it and then charge. Well, I built it (wasting way too much money on an original solution when existing solutions could have done just fine), people came (after I bent over backwards trying to onboard them), but time sucked me dry and I was not able to sustain the "business" any longer. Looking back, I did just about everything wrong.