I am a Chinese and I am learning German on Duolingo in English and sometimes learn English in German. I am on my 561 day streak today and I find it is very useful.

Before practice I can learn the related grammar and the newly added stories feature and tinycards function is of great help(glean words in context).

But it doesn't apply when it comes to unpopular(frankly speaking I am a Chinese and several years ago I tried my best to find a partner for English but failed) languages like Chinese.

Have you considering paying someone?

Since friends will be hesitant to correct you when you make a mistake, I recommend iTalki (https://www.italki.com) as it is considerably less inexpensive than in-person lessons/practice.

I would think Chinese is a pretty popular language for people to learn. Did you try the local university?

I am on my 561 day streak today and I subscribed to Duolingo plus a month ago to repair my streak because my streak broke due to the jat lag disorder in the U.S.A. Before that I kept a 80 day streak but didn't know how to fix it when I just skipped just one day.

Now it becomes a part of my routine to practice German on Duolingo. Everyday for only about 10 minutes, and I like the Duolingo stories feature very much now and I can practice even for about 30 minutes on weekends.

Actually we can jump up a level directly with fewer than 4 mistakes. To take the level 4 test we only need to take three additional tests which would cost only about 20 minutes.