Name the job the images need to do
A family keepsake, a wedding story and a portrait for a professional profile are different projects. Think about where the photographs will be seen, who needs to appear and what the final collection should communicate. A clear purpose makes the other choices easier.
Match the approach to the occasion
Documentary coverage leaves more room for events to unfold, while a planned portrait session allows more control over the setting and light. Many projects combine both. Ask a photographer how they work through a complete session and how much direction to expect.
Write a short brief
Include the location, timing, people involved, intended use and anything that would make the session easier or more comfortable. A handful of priorities is more helpful than trying to prescribe every frame. Leave enough flexibility for the photographer to respond to the day.