1) Provide ping pong balls and other toys that induce play. Play is comprised of both physical and mental exercise. Ideally both are used at the same time to provide the ultimate form of stress relief for the cat. Many cat behaviorists advocate on behalf of the cat population by educating on the best toys for cats. Toys that don't provide both mental and physical exercise at the same time are essentially useless, namely the laser pointer toy.
2) Broaden the play area and living space of caged cats and free roaming cats. This can be accomplished by the implementation of shelving units and cat towers. The best cat tower is sturdy while promoting several sleeping and playing area that suites the exercise needs of the domestic cat.
3) Scratching surfaces. There are many scratching surfaces available to cats and in many different forms. There is vertical scratching post and horizontal scratching posts, made from wood all the way to sisal rope. Each individual cat might prefer one form of scratching and type of scratching post over another. Just like humans, cats have their preference.
4) Teach cats to feel confident by teaching them that the environment around them is okay. This is best done by subjecting a cat to grooming, bathing, medicating procedures and human interaction at an early age. A well trained pilling technique and grooming habits are a must. Know when pulling a mat is too hard on the cat and warrants a veterinary visit.
5) Multiple resting areas, eating locations and active water locations. Some cats can be very particular about having their own areas for defecation, sleeping and eating. One litter box per cat and water fountains can only help improve the lifestyle of each cat in the household and ease the stress level significantly.