Take note...
1- Memorize singular and
plural
adjectives together.
Plural adjectives are
tricky if they experience internal structural alterations
that are very different from their singular counterparts.
2-
But on a good note: Adjectives have only one plural form.
Now that makes it a little easier,
doesn't it!
3-
Develop an ear for the plural form of adjectives.
Notice recurring
patterns in sound for different groups of adjectives.