Found my answer...

Four Ways Mirrors can Enhance your Feng Shui
by Karen Rauch Carter

Get the guidlines to using mirrors from feng shui guru, Karen Rauch Carter.

Mirrors can do several things, depending on your intention:
1. They can erase
When you have a wall too close or in front of a doorway blocking "good chi," you can add a mirror to "push that wall back" and give that area more space. Make sure you can see your whole head when you put up this mirror.
2. They can double things
Since oven burners represent prosperity, you can create the illusion of having eight burners instead of four for a prosperity boost. Just add a mirror near the stove to reflect the burners. A little one will do here -- perhaps four to six inches in diameter.
3. They draw in
For instance, if a room is "outside the bagua," you can add a mirror to face the missing "gua." I'd say an average is about eight to twelve inches in diameter for this. (Note: if you're lost on this one, see more about the bagua right here.)
4. They deflect
If you have not-so-lovely neighbors you can point a mirror toward their home. I usually try to deflect them away from the farthest point I can. If you have a yard around your house and you are trying to keep away the obnoxious neighbors, then put the mirror against your fence at the property line! If you can't to that, just place it up against an interior wall facing out toward their house.