Writing a business plan is usually a priority in business, some do it well, some do it poorly, but what most do not do is write a business plan that evolves.
Effective business planning considers the long term context in which the business operates, and how the resources are to be allocated against the priorities, but shorter term, most tend to be fixated on a period, and the plan becomes a “set in stone” folder articulating financial outcomes that are as often as not wishful thinking, and in which all but the short term tactical stuff is dismissed as “too busy right now” to do.
Really effective planning engages with the reality of the environment right now, considers how the longer term direction will be impacted, makes judgments about emerging trends, and marshals resources and capabilities .
So, in summary to be effective:
Revisit the plan often
Reevaluate the risk assessments
Experiment and evolve.