Here's what my teacher did:
- on rectangular small bits of paper, she had the certain masculine, feminine, and neuter endings, only one on each. (Then the more typical, but not a rule endings.)
Masculine
More typical masculine
- -ich
- -ing
- -ling
- -or
- -us
- -ast
- -est (double check)
Feminine
- -e
- -heit/keit
- -schaft
- -ung (there's one exception I know to this ending, and that's der Stimmungsumschwung)
- -ion
- -ik
More typical feminine endings
- -a (a lot of confusion with "ma")
- -age
- -anz
- -el
- -enz
- -tät
- -ur
Neuter
More typical neuter endings
- -at
- -ett
- -icht
- -ma (causes confusion with "a")
- -nis
- -sal
- -tal
- -tel
- -tum
It's easier if you know an example for each one.
Align them out under "der" "die" and "das" respectively, and then go through the endings so that you can recall an example for each one.
Then mix them up, and put them under the correct category. Keep doing this until you get all of them correct.
Find some written practice exercises online if you can.
There are irregulars in the more typical endings, so go online and find a game which will help teach you the most common ones.
Here's the examples I used.
- der Konig
- der Sportler
- der Terrorismus
- der Elefant
der Terrorist
(can't remember one for "-ich")
- der Frühling
- der Frühling
- der Direktor
- der Bus
- der Palast
(I think I remember "-est" being mentioned, but double check. Can't remember any examples to confirm.)
die Karte
- die Gesundheit/die Möglichkeit
- die Freundschaft
- die Bewegung (with that one exception)
- die Lektion
die Musik
die Firma
- die Etage
- (can't think of one for "enz")
- die Etiquette
- die Realität
die Tur
das Brotchen/das Mädchen
- das Fräulein
- das Forum
- das Stipendium
das Gesicht (though if it has an "-e" feminine, it usually takes priority, I think)
das Diktat
- das Bett
- das Licht
- das Thema (confused with "a" of
feminine)
- das Ergebnis
- das Schicksal
- das Tal
- das Mittel
- das Eigentum
.
.
. P.S. Learn how to do this first before going onto plurals, don't try to simultaneously do both.
Now, to form plurals.
To form "der" plurals (the hardest gender), add an umlaut (ä, ö, ü), and an "-e".
2nd way is to just add an "-e"
- der Film --> die Filme
- der Hund --> die Hunde (no umlaut)
3rd way is to just add an umlaut
- der Apfel --> die Äpfel
- der Bruder --> die Brüder
- der Garten --> die Gärten
Or no change.
- der Lehrer --> die Lehrer
(all the examples I see of this seem to be e.g. a teacher, butcher, runner waiter, Englishman etc.)
"die" feminine words a lot easier :)
usually '-n' or '-en'
- die Tasse --> die Tassen
- die zeitung --> die Zeitungen
"-in" on teacher, schoolgirl etc. simply becomes "-innen"
- die Lehrerin --> die Lehrerinnen
- die Schülerin --> die Schülerinnen
A few "die" words add an "-e"
- die Stadt --> die Städte
- die Kuh --> die Kühe
"das" words
either add an "-er", and an umlaut if possible
- das Kind --> die Kinder
- das Buch --> die Bücher
or add an "-s" (Generally loan words, I think)
- das Auto --> die Autos ('Auto' used in many languages.)
- das Hotel --> die Hotels
or an "-e"
- das Jahr --> die Jahre
- das Haustier --> die Haustiere
This took over an hour to write (70 minutes I think), so I hope it was useful.
It's a bit messy, as I never preplanned the structure to it.
Go through it bit by bit, making notes, slowly working your way through it like a booklet as it probably looks really daunting. Also very helpful if you had someone to test you.
Make some nice summaries, as this can be summarised to remember better. perhaps on the back of the cards/pieces of paper put the example.

P.S. I know this isn't the entirety of declensions in nouns, but it's something. I'm nothing of an expert either (only recently started A2), so people correct me if I'm wrong, please.