This is the first post in the "Mistakes I made" series, where I share the "donts" of my startup experience.
One of the valuable lessons I've learned is - give up on failed projects easily.
I have bought a project once - a PC security utility, developed by an Eastern European company. I thought I could market it better than the founders, find new niches for the product, polish the interface, add more features etc.
Long story short - I failed. Couple of months later I even discovered that it had serious compatibility issues with Windows 7...
But I couldn't let that money go. I kept redesigning and promoting the website. I kept hiring freelancer programmers to deal with the Windows-7 bug (it required some hardcore C++ and WinAPI knowledge that I don't have). I desperately wanted the project to pay for the spendings I threw in it, so I threw even more. But what I really should have done - is close the project. And stop trying to cure a dead creature.
There's no typical criteria, like "if there are no sales within a month - stop it". But there's always a point, when you can tell a failure from a... slowdown. Our web-based help desk was not making any sales for months after the release, but we always knew that it would at some point. It's just a competitive market to be in, we needed more features, more marketing...
Eventually there are ways to benefit even from abandoned projects: by making them free and attracting some "link juice", for instance. So, have the guts to let go. "Failure should be your greatest teacher, not your undertaker."