The Strobist “Lighting 101” blogpost posits seven decisions about applying a strobe:

Once you have your flash, the question is how to better use it.

Briefly, your decisions are:

• Where am I going to put the light – and why?
• How am I going to get it to stay there?
• How am I going to trigger it?
• What will the quality of the light be: Hard or soft?
• What will the beam spread of the light be – wide, narrow?
• How will I balance the strobe’s intensity with the ambient light?
• How will I balance the strobe’s color with the ambient light?

There you go. Seven decisions you get to make, with an infinite number of possibilities. And that is just assuming one strobe as a light source. Very soon, most of these variables will get to be instinctive, and you can concentrate on the two or three that will define the quality of light in your photo.