One of the common issues I run into with startups I advise is a problem with abstraction layers/granularity of planning.
Plans that are either too high level (E.g. Take over the world in 3 years) or too low level (E.g. ticket 1, ticket 2).
Remember to develop and maintain a mid-level plan that acts as connective tissue between high-level goals and extremely tactical tasks. This plan should represent milestones of meaningful, new value delivered to the market (E.g. "Introducing New Feature X").