Starting something is not a difficult task, but working on it and completing any task is very typical. Many times this happens, that we think about some passion or some point of success and start our journey to reach there but sooner or later we get tired of it or say we do not find it doable or boring and leave it in the middle. This feeling of not finding ourselves capable of doing what we thought to do ruins the efforts that we have done to date.  Getting motivated is easy while getting demotivated is easier, but some ways keep you motivated in adverse situations as well.

1. Keep your goal in front of your eye: write your goal on a piece of paper and stick that paper in the place that remains in front of your eye while you work. Maybe on the wall that is just in front of you when you sit at your workplace. 
2. Find reasons: every day try and find a new reason to achieve that goal. Every time people stop you from doing your task, manipulate what they said into what you want to hear, into something that makes you more powerful. 
3. Give your best but also take rest: while working for your goal give your best, don’t let other thoughts or other ideas mislead you. Whenever you feel like getting distracted go and sit in your chair in front of that wall, your dream-positive wall. When you feel like getting tired have some rest, try some different activities that make you happy. But at the end of the day again swear to start the new day following your goal.
4. Make mistakes, it's okay: it is common to make mistakes while working, but make mistakes to learn from them, not to get irritated and leave everything. And the most important thing, consider every mistake important, when you make a mistake, stop there for a while, think about it, learn from it, and correct it. DO NOT repeat that mistake ever again. 
5. Success is a long journey: people easily get demotivated when they see the results not according to what they thought. Don't do this. You have to travel a long journey to get success. It takes years to get success. Go step-by-step. Measure your work at every step. If the success is not according to the work done, try and find the reason and work on it. Whenever you feel demotivated search about your ideal, how much time it took, and what efforts that person made to reach there and compare it with your efforts, you will get motivation.