Assuming the models are looking for photos for their portfolio, then you just tell them to bring along some outfits that they want to use and you shoot a variety of shots in several outfits. Plan to spend half of the tfp shoot doing with the clothes and props they want and the other half with the things you want to do. It helps to have an idea or a theme or several themes. For example, I like to shoot around a theme of 50's pinups and many girls like that idea and think it will be fun. When I shot with Haley that was our concept and here was an example
Re: Advice from veterans
If you have trouble with posing ideas, then pick up one of the little books that have 1000 poses and then you can work from those when the well runs dry. You can also do clips from magazines and have the model work from those. I also use things like the illustrations of Gil Elvgren for posing ideas.
Just shoot a lot of variations of each pose and idea and that will give lots to choose from.