A model-photographer collaboration works best when the purpose of the shoot is clear to everyone. Start with the kind of images you want to make, the intended use and the practical limits of the session.
Prepare a shared brief
Describe mood, clothing, location and any lighting requirements in ordinary language. Reference images can clarify a direction, but the plan should leave room for the people involved to contribute. Discuss boundaries and arrangements before the camera comes out.
Keep permission, credit and delivery expectations explicit. For a personal portfolio project, agree on the selection process as well as whether participants may publish the final images.