There are plenty of pointers posed HERE
. And specifically here
, but there are many threads similar to yours all through out that forum.
As for focusing...make sure you are not too close, check your cameras minimum focusing distance and make sure you are at least that far from the subject. Make sure what your shooting has plenty of contrast for the camera to lock onto, a little trick here is to use a laser pointer or pen light to help the camera aquire focus, then remove the pointer or light and snap your pic.