It is often fairly easy to describe what the ambition of your idea or startup is; where is it that you strive to be in, say, 5 years time? What is the outcome you are looking for? The dent in the universe you are looking to shape?
What is often neglected on a planning level though is the journey to get there. Even if it can actually be a quite simple thing to plot:
Start with the end goal. Ask yourself what needs to be true in terms of results to get there (in a headline format), and then look at what needs to be true or done to get to those results etc. In that way you can essentially reverse engineer your journey, and – voila! – you have a first simple roadmap for what you should be focusing on to get to the ultimate destination.