CuriousKitten wrote:
study your special interests and/or write about your special interest, in German.
Yes, this.
You cannot make a special interest happen, but you can harness existing special interests.
One way to get people (e.g. illiterate adults) to learn to read is to give them material in a subject that interests them. For example, if they are interested in motor bikes, you give them motor bike magazines and sales brochures about motor bikes. They look at the pictures and you point out words - they are motivated to learn those words, they
want to understand the articles and sales descriptions.
I improved my ability to read a German dialect by reading translations of the first two Harry Potter books in that dialect. I already knew and liked the books in English, and they were written for 9 year olds anyway. So reading them in translation was fun, and I re-read them in that dialect many times because I enjoyed them so much. My strong interest in HP and my special interest in the dialect worked together, to do lots of reading drill and improve my fluency and literacy.
So, get some German books about your (non-German) special interests, whatever they may be. You can buy them online from Germany, or sometimes from American booksellers (e.g. Amazon in the US carries some German titles, and amazon.de in Germany sells heaps - I have bought from there).