Proper bike maintenance starts with cleaning.
A new race bike should be cleaned at regular intervals. A mountain bike should be cleaned after each ride.
It is important that you use cleaning products specially designed for bikes. Never clean your bike using regular cleaning or washing agents. This could cause damage to parts or to the frame.
Do not use a garden hose, but a bucket of water and a sponge. This will also prevent damage. Pay special attention to the saddle and the handlebars. These parts may be made of materials that absorb water. Also pay attention to the brakes. A wet brake reduces braking performance.