Adjectives are marvelous, but here are three places where they run awry:
First, we dilute their power when we stuff too many of them into our sentences at once. Instead of stuffing three or four adjectives into a sentence to describe something, try to pick just one really good one. Sure, there are plenty of times where more than one adjective is needed (“…a cold, dark night…”) but make sure they each hold their own space, and each convey something the other does not.
Secondly, and related to the first point, if you find yourself using several in a string, first of all don’t do that, but if you must, go back and read the sentence out loud. If it’s a mouthful to you, it’s a mind-full (not in a good way) to your reader.
Finally, remember the adjective must be applicable to the reader. The “delicious cake” means nothing; instead tell me the quality that qualifies it as delicious.