A finer point.

The best way to sharpen lead or coloured pencils is to use a scalpel or a small, sharp knife; this way one side of the lead can be shaped for wide lines, the other for extremely fine lines.
A real connoisseur would also have a small piece of sandpaper to hand, to rub the tip of the lead from time to time: the pencils remain sharp without having to be constantly shortened. However, if you prefer to use a small pencil sharpener, you should make sure that the blade is always sharp.