Ask HN: Startup failed. What do I do now?

I had an opportunity to build a modern web based behavior assessment system. It went well with the first client but, I couldn't market it to other clients. With savings in bank account dwindling, I quit on marketing the product and started working on contract gigs to keep a positive cash flow. I was not able to figure out what is wrong with the product and why prospective clients even after a trial period didn't convert to paid subscriptions. I guess the product is dead. Now, I can't seem to get another product idea going. What should I do ? Should I keep doing these contract gigs and try out new ideas, or should I find a job with Top tier companies. Btw, I am pretty good with computers and building softwares that run on them and on browsers.