Listening to SmartPassiveIncome podcast session 15, I learned about InfoBarrel. A website where you can put articles and get paid when they are viewed.

This is a good way to start to write, and the article must be at least 350 words, so it could fit with the 500 words a day of Jeff Goins. You double the motivation, earn money and complete the challenge.
Now, we just need to find a subject to write about.
In the Podcast, Pat Flynn is talking about what subject you need to choose. In summary, choose something that you like and can write about for very long. Choose something you're passionate about.

So I might start to write some articles on InfoBarrel, I just need to find a subject. I like to learn, so I might learn about something and write about it. But it might take more then a day to write more them 500 words.

Has Micheal from ScrivenerCoach did, if you have a hard time learning about something, that's maybe a need.

Happy learning.