I've been learning German since October. It's gone fairly well, when I focus on it I improve very fast, but I have motivation issues and have plateaued, or maybe even regressed a bit in the past two months.
The most important thing of mine for learning German is I keep a notebook of every word I learn. I have pages dedicated to nouns, pages dedicated to verbs, and pages for everything else.
I always put the article of the noun before the actual word to remember gender. For verb pages, it is set up in columns so I can write down each conjugation of it, which helps with memory even if verbs are conjugated the same way nearly every time.
This notebook is vital in remembering, studying, and looking over German words. I suggest everyone does it.
To learn more words, I'll use Duolingo every now and then, though I'm not a fan ever since they've axed the old tree layout. I also use the [https://www.youtube.com/watch?v=4-eDoThe6qo](Nico ist Weg) movies on YouTube that are made at each level of German, helps greatly. [https://www.youtube.com/@EasyGerman](Easy German) on YouTube is also fairly helpful. Besides that, I just try to interact with the language whenever I can.