Write down all the goals you want to achieve in life, ranging from short-term to long-term goals. Look at these goals every day to remind yourself of what your priorities are.
Believe in yourself. Focus on your strengths and how you can rely on them to achieve your goals.
Stay humble and hardworking toward your goals. It is going to take everything you have to reach them. You'll have to work every day toward making your dreams a reality. But think about the day when you finally can sit back and relax knowing that you have accomplished your goals and your heart's desire. This should be all the motivation you need.
Don't worry about the doubters or naysayers who constantly tell you that you can't do this or that. Never let anyone make you believe that you can't do something. Prove it to yourself that they are wrong.
Spend your time with other successful people, especially people in your field of interest who have already accomplished a goal like yours. Let them be your mentor and it will help motivate you.
Be patient with yourself. Rome wasn't built in a day, and some days won't be as productive as others. That's just part of the process. Tell yourself you're doing the best that you can.