Set a goal. If you have a major goal, it would be a good idea if you split it into several minor goals, each small goal leading to your major goal.
By dividing your goal into several, smaller goals, you will find it easier to motivate yourself, since you will not feel overwhelmed by the size of your goal and the things you have to do. This will also help you feel that the goal is more feasible, and easier to accomplish.
Understand that finishing what you start is important. Hammer into your mind that whatever you start you have to finish. Develop the habit of going to the finish line.
Socialize with achievers and people with similar interests or goals, since motivation and positive attitude are contagious. Associate with motivated people, who share your interests.
Never procrastinate anything. Procrastination leads to laziness, and laziness leads to lack of motivation.
Persistence, patience and not giving up, despite failure and difficulties, keep the flame of motivation burning.
Read about the subjects of your interest. This will keep your enthusiasm and ambition alive.
Constantly, affirm to yourself that you can, and will succeed.
Look at photos of things you want to get, achieve or do. This will strengthen your desire and make your subconscious mind work with you
Visualize your goals as achieved, adding a feeling of happiness and joy.
Remember, if a certain goal is really important, going through the above steps will strengthen your motivation, and keep you going forward.