Better retaining your language learning
I have learned about a website called Coursera at https://www.coursera.org/ in which a person could take a free online university course in another language. I understand that not all the languages offered there match the ones offered on Duolingo but I think it still helps a user to learn more about the language. They offer many different types of courses for different types of people from Medicine type courses to History type courses. They help people learn all sorts of different things and to make things better you receive a Statement of Accomplishment after you finish the course successfully. So I want to know how you reinforce your learning and retention in a new language. Feel free to comment below.
Find a local group which meets to have conversations in your chosen language. European languages are very popular and you generally will have little trouble finding one that is convenient for you.
Failing that, or simply finding that environment disagreeable, I like to talk to myself in (limited) French. When you see things in the worlds around you, try to make short sentences around them in your chosen language.
Watching movies/shows made in a country that speaks your chosen language is also fantastic and gives you both the linguistic and cultural experience.
I also talk to myself, describing what I am doing and seeing. I also like to watch German shows. It should probably be discouraging, since I can't understand the vast majority of what is said... However, I am encouraged, because I notice I am catching the occasional word I know, and I even understood a whole sentence once.
Watching the shows and movies can also help a person get used to hearing the language at a normal speed. When learning, we often hear everything said in an unnaturally slow speed (which I think is also necessary to really know what you are supposed to be saying at first).