So here's how you use focus lock. Before you actually take the photograph, place your subject dead center in your viewfinder. Press halfway down on the shutter button, but just halfway down, so the shutter doesn't go off. Now what you want in focus will be, just like this picture of Emma. What do you like better, Emma's face in focus or the flower?
A great article on this subject is this one: click here.
With many cameras that have manual features, you can also set the point of focus. It is worth the time to get out your camera's manual to figure it out.
What, am I the only one who reads my camera's users manual?