How can I get better at learning German??
It's especially important at your level to listen to podcasts. I wish I did that. Here is a really good podcast with currently 196 videos. They speak really slowly in this series but slowly progress faster as you presumably learn.
I started Duolingo because I really wanted to get back into learning German again. So far, using duo, daily if possible, has been a tremendous help. I also got a Hammer's German Grammar and Usage text to further my understanding of the language. Of course, there are many resources on the internet - you just have to find one you enjoy using consistently. Also, I gathered a couple of friends on duolingo to make learning more fun. We compete to see who can gain the most XP per week mostly for light-hearted bragging rights and a little motivation to keep going. Best of luck!!!
In addition to what has been said, practice daily. Even if it's only 5 or 10 minutes, do something every day. I have been practicing this for 174 days now. I had a 20-some day streak going before this, but missed one day.