When former students contact me, they're often seeking the Rosablatt (or pink sheet.) That’s literally all it is. A pink sheet of German grammatical goodness.*
This grammar chart, along with step-by-step guiding questions, represents my best attempt to help you make sense of Jakob Grimm’s beautiful word ending system—declensions for articles, adjectives, and nouns—updated for this millenium and honed over seventeen years of teaching high school German.
When former students return for worksheets, you know you have something good.
*Pink paper not included. You might also check out the green verb sheet.