Listening and understanding what you hear is an important part of learning German if you ever want to be able to communicate with others in real-life. A good way to improve your listening skills is to listen but not just randomly. Many learners listen to podcasts regularly and that’s good for getting used to the sound of the language and it’s nice if you can understand a few words. But unless you’re on a higher level, this will not support your progress.
What you can do is work with listening material that you can get a script for. If you work with a text book, there are often CDs included and they have a script section in the book. This is a good choice for a beginners level, as the audio bits are small and adjusted to that level. You can also get audio books and the written version of them. Non-fictional books on everyday topics are a good choice here if you are on a medium level. There are also some websites that offer audio plus the script.
First, ignore the script. Only listen to the audio. Pick a certain part of it – not a complete book, but a limited time of speaking, maybe a couple of minutes – and listen to it multiple times. Then try to listen to it again, pause it after a sentence or after a few words and write down what you can understand, word by word. When you have finished writing everything down, listen to the audio again, go through what you have written, fill in the blank parts where you can and make corrections.
Now is the time to look at the script. Listen to the audio again while reading the script parallel to it.
Look up all the words that you didn’t know, so you really understand the text.
Check how much of the text you missed because of words you didn’t know and how much you missed although you actually knew the words and just couldn’t understand them when you heard them.
If you had to look up a ton of words, try to find an easier text. If you didn’t understand the words you knew, stick with this same material (type and topic) and do this same exercise over and over.
Do that regularly, keep your notes and after a few weeks go back to the first audio you worked on – you will be surprised at how much better you can understand it.