Do you get news in different languages on TV? On one of our channels, we got news in all sorts of different languages, including German, from 6 am to noon on Saturdays and maybe some other days as well.
If you do, spend an hour or so each week watching the news in German while continuing to do Duolingo several times a day. The thing with watching the news is that if you watch the news in English too, you'll have an idea what the news story is so you can pick up some of the German words. It also helps to hear it constantly spoken for an hour or so.
Before our trips to France, I used to turn on the French channel and watch it a few hours here and a few hours there.