Before you fiddle with anything, always make sure to back up your system. If you aren't already using the built in Time Machine app, you really should be.
Go to Disk Utility by typing in Disk Utility in your spotlight (top right). Once in Disk Utility click on your hard drive on the left side of the screen. Then, down on the right side click Verify Disk
Restart the computer and hold down the ALT/Option key. Let go when a grey screen with two hard drive icons shows up.
Click on the hard drive icon that is label "restore" (or some variation of that)
Select Disk Utility and then click continue
Select your hard drive right the left side of the screen and click Verify Disk. After it completes, click repair disk, then verify permissions, then repair permissions. Always allow the computer to complete each process before moving on to the next.
Restart the computer and let it start up as normal. You will likely see a grey screen for a few minutes with a progress bar moving. After the computer restarts, look at your spotlight. A pulsating dot should be seen in the center of the magnifying glass. Let the computer sit while this dot pulsates and don't open any applications.
After performing this bit of maintenance I noticed my computers both ran much faster than they had right after the OSX update. I was ready to spend some money on more RAM until I read about this tip. I may still do that (who doesn't want more POWER?!) but until then, this fix will keep me going with the same speed and consistency as I had in Snow Leopard.
Comment below if you have questions!