Pot plants in the house should be secured to shelves to avoid injury to cats knocking them over or provide a cat tree or shelf to get upto the window sill without knocking the plants over. Spray house plants with bitter apple to make them bitter tasting to cats.
Avoid Lilies as the pollen is toxic to cats and humans. Grow cat grass kits (see garden centres) as grass helps digestion. To stop cats digging in planters try using large cobbles to cover the compost.