Have vertical spaces Cats need to be able to see things from above. They will feel more confident and are happier if you allow spaces for them to walk on. Create more vertical space. You can add empty shelves on the walls or have tops of the tv, tables, mantles clear for kitties to walk on. Cat towers can also provide additonal stimulation. Add stepping increments. If your cat hides a lot, please try this approach.
Have toys available Cats need to hunt and kill to fulfill their needs. This can be done with mouse toys, balls, etc. You can also try to play fetch with your cats or purchase a stick toy with something on a string. Give them some one on one time like you would your child. This will help you and your cat to bond and burn off some energy for your kitty.
Have wheat grass available If you find your cats eating your plants, that is your clue that they need vegetables too. Wheat grass or cat grass can fulfill this need. You can also purchase your own seed to plant and grow regularly for them.