Whenever you find a defect, ask why five times to discover the root cause of the problem. Then make corrections at every level of the analysis. By applying five whys whenever you find a defect, you will (1) uncover the human problems beneath technical problems and (2) build an immune system for your startup.
(Full Post: http://venturehacks.com/articles/five-whys)
Babak Nivi is a co-founder of AngelList and Venture Hacks. Previously, he was an entrepreneur-in-residence at Bessemer Venture Partners and Atlas Venture. He has worked on startups including Songbird, Grockit, and Kovio. He went to school at MIT where received 2 patents and published in Science.