Let's say you need to learn a list of words for a test. Spend
ten minutes learning as much as you can, then put it away.
A half hour later, spend another ten minutes. Two hours
later, spend ten more minutes. Then review it all again
the next day, then a week later. When you're repeating
it, you can obviously start spending a shorter amount
of time when you find you've learned everything.
The best idea: don't learn it all at once!
big advantage of this is that you will be much more
likely to remember the words you learn in this way after
the test is over. It also involves much less stress,
and you can do it in little time slots when you could
normally not do anything else useful, e.g. when you're
on a bus or maybe even in the bathroom.
The other best idea: form sentences with the vocabulary you're learning or reviewing.
In general, "mechanical" strategies like covering the words up and testing yourself on them systematically until you know them all will work best for the test that's in 5 minutes, but you're not likely to retain words you learned this way for very long, because you're not likely to "integrate" the new vocabulary you learn this way into the German you actually use.
==> In the long run, the best strategy for learning and retaining vocabulary is to form as many sentences as you can as quickly as you can with the vocabulary you're trying to learn or review. Simple ideas include saying (for nouns:) "Ich mag X/Ich mag X nicht," (for verbs:) "Ich X gern/Ich X nicht gern," classifying things [X ist...] into gut/schlecht, groß/klein, ein Ding/eine Idee; forming sentences relating the word to famous people etc. If you do this, you're killing two birds with one stone because you're also simultaneously building fluency by training yourself to come up with German sentences more quickly.
To review vocabulary from previous courses (a very good idea, even if you did very well in these courses!), pick a realistic amount of time you can invest each day, e.g. 5 or 10 minutes, and then e.g. spend 5 minutes today forming sentences with the Kapitel 1 vocab, 5 minutes tomorrow forming sentences with the Kapitel 2 vocab, 5 minutes the next day forming sentences with the Kapitel 3 vocab, 5 minutes the next day forming sentences with the Kapitel 4 vocab etc., and start back up with Kapitel 1 when you've reviewed them all in this way.
You can also have fun doing this by giving yourself permission to create silly sentences, like "The bandaid catches a cold" [Das Pflaster erkältet sich] or "I would like to have your pedestrian zone" [Ich moechte deine Fußgängerzone]. Such silly sentences might come back to you when you encounter these words, so you'll never forget them. Especially silly sentences that you can vividly picture will be especially helpful.
Click here for some ideas for coming up with a bunch of sentences quickly!
3. Make meaningful groups
is also very helpful: spend some time organizing the vocabulary
into groups that are meaningful to you. Not every word
needs to fit a category. This will make your mind actively
engage with the words and this processing helps you remember.
Ideas for categories: meaning groups (the most obvious);
things you hate vs things you like vs things you are indifferent
about; ugly words vs pretty words; short words vs long
words; easy words vs hard words....
of the remaining strategies are a bit time-consuming,
but very effective ==> I suggest that after you've looked
at the words a few times and when you realize which
ones are giving you trouble, you try some of these strategies
to help you with those "troublemakers."
ones like "hoffen" and "hope," but also subtler ones in
parts of words, like "ausgeben" [=spend (money)] and "give"
or more distant but still recognizable ones like "Kuchen"
Make silly rhymes in German
learn "zu Fuß" [=on foot]: ich gehe zu Fuß
learn "sparen" [=to save (money, time, etc.)]: Ich spare
Make fun links to similar sounding English words.
learn "Freiheit" [=freedom]: beginning sounds a bit like
"Friday" ==> associate Friday and freedom
learn "benutzen" [=use]: middle sounds like "nut" ==>
picture yourself using a nut to crack open a safe or
learn "aussteigen" [=to get out of]: middle sounds like
"sty" [as in "pig sty"] ==> picture yourself or someone
you know getting out of a pig sty covered in filth
big advantage: once you have them, you have them forever.
And they associate your learning with physical activity
etc. And you learn as you write them.
disadvantage: You often find after making the cards
that you have no time left to use them ==> It's great
if you make these, but make sure you have time to use
people swear by this: play some slow, relaxing baroque
music in the background while you slowly say the words
(or anything you want to learn!) to yourself, and your
brain will be "in tune" with this.
code the genders on your flashcards, e.g. every feminine
word is yellow, every masculine word is blue, every neuter
word is green, or whatever colors suit you. If you don't
have time for this, try to just see these colors in your
head each time you see a new word.
"Feel" the Gender...
to train yourself to feel a specific physical sensation
every time you see a certain gender. E.g.: Neuter: feel
nothing. Masculine: feel cold. Feminine: feel hot.