After several days to a week, let the resident see the new cat by means of a screen across the doorway or by placing your new cat in a crate within the room. Give them short periods of contact, slowly increasing the time as they adapt. You can also exchange items with each cat's scent to help familiarize them with one another. When they get close, there may be some hissing and growling-but doesn't permit physical contact until your resident seems comfortable with the new addition. They may never do more than tolerate one another, but on the other hand, many cats become fast friends.
Bowls designed for pets, made of metal or ceramic, are best.
If you're feeding dry food, clean them at least once a week and more often if feeding canned food. Make sure the water bowl always has fresh water. Cats are creatures of habit and feel most secure on a regular and predictable schedule. This is especially important when your cat is first introduced to a new environment. Feed him in the same place and at the same time each day, and condition him to regular schedules of attention, grooming and play.