I used this powerpoint to emphasize how adjectives are used. At the end, I have the students make "adjective posters" - big pieces of colored paper, and they write sentences on them. I've been hanging them in the classroom for decoration, and the students can see that they are good at making sentences. It's also nice to have the posters to point to throughout other lessons. I let them make the posters for about 15 minutes, and then leave enough time to present.
This is geared towards all-girls high school, so you may want to change some of the photos, etc.
I also use a page with adjectives to help them think of new words to use. (I borrowed it and changed it up a bit from another waygooker - so thanks!)
Enjoy!