Motivation is the characteristic that helps you achieve your goal. It is the drive that pushes you to work hard and reach whatever it is that you are after. It is the energy that gives you the strength to get up and keep going - even when things are not going your way.
Unfortunately, we cannot buy motivation - it is not something that is bottled up and sold in shops. The good news though is that we can all cultivate this 'motivation'. The only thing we need though is a desire to change. We then need to work on ourselves, conquer our fears and push ourselves forward to reach our desired destination.
Motivational books are one of the prime ways through which you can motivate yourself. Listening to some inspiring music is another way - attending motivational seminars can also have good, long lasting effect on your lives.
Motivation can be intrinsic or extrinsic (internal and external) - With extrinsic motivation, you are motivated by rewards from an external source - you will be inspired by the recognition that you will get from external sources. Intrinsic motivation is something internal - you are motivated to reach your goal for your own internal benefits - Example - reading a book so that you can get the grade you are after versus reading a book so that you can learn something.
Intrinsic motivation is better than extrinsic motivation. But for many finding intrinsic motivation is not easy - it has to come from inside out. But once you get it, intrinsic motivation is much more powerful than the extrinsic.
Levels of motivation can go up and down. When you are down, it is important to work on yourself, by reading books or whatever helps you, and get your motivation levels up. Otherwise you lose the purpose in your life and it can affect your mental and physical health.