Having a plan of action before you go to the gym can help you avoid wandering aimlessly around while you decide what to do next. This indecisiveness not only adds time to your workout, it also makes it less efficient, since you’re letting your heart rate drop. Know what exercises you’re going to do, where you’re going to do them, and in what order.
It’s also a good idea to have a plan B, just in case the machine or floor space you were planning on using is taken. Move on to other parts of your workout and come back, or be armed with a backup exercise in mind that utilizes different equipment.