It's good to go back and re-examine your failures, so you can see where you are weak, or maybe it's not you but someone in the team. Or it could be a person in your personal life. I've found one thing that I had a lot of issue with: you as the creator are trying to develop a dream into something tangible. Sometimes your partners may have great skills and a wealth of information to contribute, but they have the job mindset. You see the big picture which means you need to manage all of the "moving parts", your partners can get stuck on perfecting one part of the project more than necessary.