Are you in English training at the moment?
A weekly class is one key step for improving your English, but adding a few more "vitamins" is another important step.
Look for English podcasts, news websites, TV series, movies, magazines and books that match your interests. Help your son or daughter with their English homework. It's okay if you don't understand everything the first time you hear, read or watch it. It's also okay to watch a TV series or movie in English while reading German subtitles -- and then someday changing the subtitles to English.
Clients who integrate English into their lives outside of English training often improve their skills more quickly than those who don't.
Which "English veggies" will you be adding to your diet?