Bringing home your new kitten once you have selected the "perfect kitten." When you chose a second cat, it is very important to match personality and lifestyle to the first cat.  If you have an older, laid back cat, he is not  likely going to eagerly welcome an energetic young kitty.  In this instance you might do better with a calm cat.  Opinions vary about the roles that age and gender play, though most experts agree that temperament and energy levels are the primary considerations. Still, there is no guarantee that even the perfect candidate will bond with your existing cat.

One you bring your new kitten home, it is important to have a room solely dedicated to the new kitten.  Provide it's litterbox, food and water dishes, bedding and toys.  Open the carrier and leave the room, closing the door behind you.  This gives the cat new time to explore its small territory without the added stress of encountering strangers.  Over the next few days, give it lots of attention and love during brief visits, but do not force yourself on the kitten.

Basic feline introductions are done by beginning to familiarizing the cats to each other through scent exchange.  Rub a clean towel on each cat, then present it to the other cat.  This enables each cat to launch an investigation to the other without the stress of an actual encounter.

Now that the stage has been set, let you cats get their first glance at each other through a cracked door.  It is imperative that you maintain control of the door so as to protect the innocent if one gets grumpy.  Although some hissing and growling is expected, lasing out and lunging are not acceptable.  Slowly repeat this step until both cats are in the same room, however, do not turn your back as you may have to return your newcomer to their personal space.  Continue to expect a little hissing and argument and even a little swatting, but try to end the session on a positive note, even if the session only lasts a few moments or so. 

Over time the cats will develop a relationship on their own terms.  Vocalization and harmless scuffles should dissipate over time as they establish a feline hierarchy.   Remember that introducing cats is not an overnight, or even a week-long process, it can take up to an average of six to eight weeks or longer.