Eliminate "failure" from your vocabulary. In entrepreneurial circles, it's often fetishized as a rite of passage, but this mindset isn't helpful. Not everything works out, and that can be disappointing. Instead of dwelling on failures, relativize outcomes: some things work out better than others. This healthier perspective acknowledges that success varies without labeling less successful ventures as failures. Don't expect to find many lessons in retrospect; the reasons for an outcome are often complex and not easily pinpointed. Focus on moving forward and learning by doing, not reviewing. Each new attempt is unique, so approach it with fresh eyes and enthusiasm.
Summary of blog by Jason Fried