I do not teach 7th graders this year, but I guess short role-plays can work. Just decide on situations and ask students act them.
For e.g. Helpful
Ask a student come to the board.
Act as if you are an old person. Carry heavy things or act as if you have difficulty in carrying.
Look him/her deeply in the eyes. Make him/her help you. I guess he/she will try to help and carry your bags.
Then tell him/her very loudly in an exaggeration : "Oh, thank you very much ! You are very helpful !" (Emphasize helpful)
Then rush to the board and write the word "helpful" .
You can do it for every adjective I guess.
After the acting sections, to check their learning, paste suitable pictures about these adjectives and ask them come to the board and write the suitable adjectives under the pictures.
Good luck :))