When it comes to piano tuning, it is vital to use a muting strip to silence the side strings in the octave, this way only the middle string will vibrate when playing a note. It is recommended that you mute at least two octaves, so that you could fine tune the strings in the middle. When using the tuning lever it is recommended that you should be held to the right so that when it is turned around, the force of the string will pull the pin free from the front side of the hole. This way the pin will be able to move freely. In the process of tuning the piano, always make sure that the pin block is in optimal condition. This must be done to ensure that there is no warmth upon turning the pin. If the connection between the pin block and the pin is warm, the change in temperature will effect the molecular structure of the wood.
The tuning lever is an important part of tuning a piano, people who are thinking of tuning their own pianos by themselves must consider getting a tuning fork for the operation. In order to use a tuning fork properly and to get the desired result of finely tuned piano, there are basic methods and procedures to follow. A high quality tuning lever is made up of sockets that connect it to the head, as well as a stretchable handle along with a second to connect to the tip of the handle. A quality tuning-lever is important, but other devices can and should be used in the process of tuning a piano. These devices include rubber wedges, a muting strip and perhaps ear muffs or ear plugs.
Source : http://pianotunerblog.wordpress.com/2014/05/19/tuning-a-piano-by-yourself/