A vision can sound compelling while accepting every opportunity placed in front of it. If it cannot help you choose between two attractive options, it may be too broad to guide the business.
Describe the intended business
Name the customers, the problem and the kind of work you want to become good at. Include what the business should make possible for the team and its owners. This gives the direction an operating meaning beyond a large future revenue figure.
Avoid making the description so narrow that it cannot accommodate new evidence. A direction should guide learning, not require defending the first idea forever.
Apply it to a live choice
Compare a project, partnership or feature against the direction. Does it strengthen a capability you want to retain? Does it serve an audience you intend to understand? What would it displace?
A financially attractive project may still be worth taking for a specific reason. Make that reason explicit rather than pretending every exception supports the strategy equally.
Record the trade-off
Write what you are declining as well as what you are choosing. This exposes the cost of the direction and prevents a strategy from becoming a collection of unrelated yeses.
Revisit deliberately
Set a point to review the direction against customer evidence and operating reality. Change it when the case is strong, not every time a new opportunity appears. A useful vision creates coherence while leaving room to discover that the business should evolve.