How to Maintain Your Piano

1. Maintain and tune the piano only by a professional tuner. It should be done at least once to twice a year depending on the piano. As if it is an old piano, the tune should be at least twice a year versus a new one you can go up to once a year. My piano was brand new when I bought it directly from the manufacture so once I noticed the slightest change in the pitch or tone, I called the professional tuner that recommended by the manufacture. It doesn't matter if you rarely play it or on daily basis as not doing so will damage the piano by causing its strings to drop and loose its pitch.
2. Warm, moist or dry air affects the piano differently. Especially be cautious from the moisture as it can cause the strings to rust. Thus, the optimum humidity of the room ought to be between 43 to 60 percent and the temperature is 640F and 73‏0F.
3. Locate the piano near an inside wall and away from any heating or calling sources, as well as drafty windows or sunlight as both cause severe damage inside and out.
4. When you are not using the piano, close the lid to avoid dust from piling up between the keys and jam their function.
5. Don't clean the keys often and if the keys get dirty, use several drops of mild dishwashing liquid to the cloth. Do not spray with water or cleaner directly on the keys. Any fluid that goes down between the keys can harm the instrument plus it can make the keys too slippery and hence difficult to play.
6. The best way to clean the piano between the keys is by compressed air or a soft paintbrush.
7. Don't pile different items above the piano or piano's lid even not decorative things. It is not a shelf and can scratch or damage its finish moreover it can alter the sound.
8. Have fun playing your piano!

Source:http://www.ehow.com/how_4860434_care-maintain-piano.html