If your ceiling fan shakes and wobbles it means one of the blades is unbalanced. An easy way to tell which blade is the culprit is to turn off the fan, attach a clothes pin to the side of one blade halfway from the end, and turn it on again. If it still wobbles, repeat this, trying different blades until it no longer shakes. Now that you know the offender, glue 2 dimes to the top of the blade to stabilize it.