I have been helping people plan for many years. One of the fundamental problems is that some who come to the table to plan want to give your their answers, right at the start.
A plan, broken down to it’s simplest form has three distinct components.
You need to work out where you want to be, by when first. Then develop the strategies setting the path by which you will get there. And finally the actions you need to take in the near term to reach these longer term goals.
For example, suppose you are a really good motor racing driver who wants to win a championship in the next three years (your objective). You will need to get a major sponsor, get signed by a top team, find a group of professional supporters (fitness coach for example, mentor), build a fan base (promote yourself and build a community of support) and compete at the highest levels (your strategies). So today you need to write a formal business proposal and develop a budget, set up meetings with potential sponsors and promote your value, engage with top teams to sell your capabilities and learn about their rosters, hire a technologist to build a social network and web presence, etc etc (your actions).
If you jump to the actions without going systematically through the process then you have the potential to miss out on some important considerations. When developing plans it is good to get those together who will be integral in the ultimate execution of the plan. The more scenarios you look at the more likely you will find the one most likely to lead to your success.
Of course it is a lot more complex than this but it never hurts to go back to first principles and test what you have done.