Nikon D7000, 85mm f/1.8, f/5.6, 1/160s, ISO 400.
You need to change two things in your camera. First, set your camera so that there is one autofocus square lighting up when you press the shutter halfway down to focus. This lets you choose where to place the focus point (using arrow keys on the back of the camera), instead of the camera guessing what you want in focus (this has different names on different cameras, but it’s often called Autofocus Area Mode).
Second, set your camera to AF-S or ONE SHOT. This setting makes the camera stay focussed on the same spot as long as you keep the shutter button depressed half way. That means you can move the camera so that the focus point is on the eye, press and hold halfway down, recompose so it looks good, and then finish pressing the shutter down (you need to practice this so that you don’t change your distance to the subject as you recompose because that will change the focus).
One more tip: If you’re shooting when there isn’t a lot of light, try using the center focus point. It’s more accurate, and will help you nail focus more often in low light (just remember to recompose so your subject isn’t always in the dead center).