Looking at other learner profiles on Duo I see lots of users start a language and give in before the bug bites.
For my own motivation I use a simple system........I brag !
I tell everyone I am learning Russian and Ukrainian. Once you have let it out in to the world you cannot give in. You can sit at home and play with the idea of learning but that means you can quit when ever you want. And you will !
Tell people. Find a strange word that sounds familiar in your own language but means something different in you chosen subject. Tell people.
Take screen shots of your progress. Show people.
Learn everyday.
If you have to miss a day, punish yourself. No chocolate bar
Watch your word count grow and brag about it.
Learn to say " I love you " in your new language.
Do not be tempted to learn curse words. They will come out when you do not want them too.
Enjoy. Find time for your lesson. I do some whilst walking. I do others whilst having meals.
Believe in yourself. No one can learn for you. No one else will benefit from your efforts. This is your chance for glory. You can do it !