Once you have found your purpose, make sure to let the world know about it. 
Find a proper reward and go after all you have always wanted all in, no matter the risks.

Find your purpose and live up to it

It might be that nothing motivates one as a reward. Knowing that you will be rewarded after having completed the task has a strong influence on your brain. 
Therefore, bet on it and, if possible, try rewards that offer you inner satisfaction and that are not necessarily related to spending money like crazy.

Rewards and motivation

Making sure you hold yourself accountable in order to keep up the motivation and, therefore, accomplish your goals, is easier than it sounds. 
All you have to do is to commit and express your commitment also in front of others. This will lead to you wanting to be consistent and, therefore, it will make it harder to give up.

Improve your personal accountability

Without purpose, motivation does not stand a chance. 
So start thinking about your purpose, what makes your inner motivation stay alive and do your best to accomplish it.

In order to stay motivated, you need a purpose

“What man actually needs is not a tensionless state but rather the striving and struggling for a worthwhile goal, a freely chosen task.”

So you commit to improving your health, career, or relationships, and after two days, you give up. "I'm not motivated." We often say those kinds of things without knowing what motivation is. Motivation is simply the reason (or reasons) for acting or behaving the way you do.