When it comes to minimizing vibration, quadcopters are exactly like RC airplanes in that, balancing the propellers greatly reduces vibration. In a quadcopter and other Multi-rotor craft, this improves performance, reduces motor and framework stress and wear, and improves the quality of your video, if you are using an aerial camera with your quadcopter.
To properly balance the prop blades you need to setup your Du-Bro Tru-Spin Balancer in an offset configuration so the propeller can be mounted as shown in the video. This allows it to spin freely without touching the top of your workbench. Next you have to attach your propeller to the proper size balancing shaft also available from Du-Bro. These shafts are available in 5 and 6 mm sizes to fit most quadcopter propellers.
Attach the propeller and place the shaft on top of the balancer and let the blades turn freely without touching them. The heavy blade will move to the bottom. You can then balance the propeller be either removing a small amount from the heavy tip blade by sanding away material on the back side of the blade, or you can add weight to the light blade. You can do this by apply a light coat of CA glue or epoxy and letting it cure. For very slight balance adjustments, you can also spray clear modeling paint on the lighter blade. Three or four light mist coats, drying between applications, will bring the blades back into balance.
Your propeller will be perfectly balanced when it can be placed in any position and it stays there. A safety note here is that if you have a very much out of balance it is better to replace it with a new one than to remove a lot of material which could weaken it.