Chris-L, it sounds as though you are just turning up and hoping inspiration will rain down on you from the sky....it won't!
You need to make some decisions BEFORE you ever see the model. Some ideas of the kind of thing to think of beforehand - to get your mind going:
High key or low key?
Narrow side light or broad light?
Narrow depth of field and only one eye in focus, or f8 and be there?
Tight crop to face only, or head n shoulders, or full length?
Sat or stood or lying down?
Clothed? If so what......
Nude? Semi nude? See idea above.
Now you can sit down and make a list of ideas of what you want to achieve. Remember, it is far better to achieve ONE GOOD PHOTOGRAPH than a whole card full of crap. So with that in mind, really focus your thinking, not just your lens. Get some ideas in your mind of what you want to do - unlike other people I disagree with going looking through others work for ideas, don't go searching like that. Better by far to open your mind and get some pictures in there, when you get an idea WRITE IT DOWN. I have a little notebook and pencil (quaint, in today's iPatch world, I know, but it still works and it is instant!) which I carry with me all the time. If I get an idea, whether for a picture a pose, a feature idea, a sales idea...anything, I write it bloody well down. If I don't, I forget it. You do the same - for picture ideas for when you have a model.
Give yourself a brief. You have a model coming, do you know which sex beforehand, if so that narrows down the thinking. What about making some abstract aptterns from the body and shadows? That works too.
Just asking us for "what do I do with a model?" is like asking us, "what career should I go into when I leave school?"
My answer will different to AliB whose will be different to AWP etc.....
Forget the camera and lens. That is the problem. Most photographers get hung up on the kit....it is the IMAGE that matters, not the blasted box and bottle.
One "rule" you could try is to ensure each limb is defined. No BLOBS. A blob is where the bodyshape is lost. Get your wife/girlfriend/significant other to just go through some "poses" at home - no camera at all, just your eyes and squint to see the effect. Move an arm across the front of the body and see how it gets "lost" and becomes a blob...now move it out and put the hand on the waist so the elbow makes a V out to the side of the body....now look how much more "shape" there is to the body suddenly.
Pleasing poses often incorporate triangles (that V of the elbow is a triangle!)
Bent leg = triangle.
Sat on floor leaning against wall in L-shape = triangle.
