You should also have them draw arrows connecting the adjective to the noun it modifies. Have them add adjectives to sentences. Have them add too many adjectives and see how stupid the sentence sounds. Then let them decide which adjectives are the most important to keep, and have them cross out the rest. Finally, it's time for adverbs.
Adverbs modify verbs.
There can be a big difference between just talking, and talking excitedly, loudly or nervously. As I mentioned before, adverbs are rather out of style, but you will use some of them. Just don't let the kids get carried away when they use adverbs. Use them only when they are absolutely necessary. Acting can be a part of your adverb lessons.