Try to place your piano on an inner wall of the room.  Do not place it too close to an exterior door or window in order to avoid direct sunlight or rapid changes in temperature or humidity. Furthermore, for the same reasons, you should never put your piano on, under or around your air-conditioning or heating vents.

Do not put your piano near an open fireplace or any unvented heating device

You should not put anything too hard or too heavy on your piano. Such items may cause a sympathetic vibration, which will affect the tone, and a heavy object may distort the top and or scratch the finish.

When placing your piano next to a wall, keep a certain distance between your piano and the wall.

Upright pianos should be no closer than 4 inches, while grand pianos should be no closer than 12 inches from the wall.  For the best sound performance, be sure to have enough area around your piano to allow the sound to escape. On the other hand, if the space is too large and or there are too many hard surfaces, you may need to place sound absorption materials near by, such as plants, carpet, area rugs, curtains and the like to limit the echo effect.

Do not move your piano too frequently.  This will help you avoid unnecessary maintenance costs and limit the chances of damage.