Does anyone have a muti-cat household where the cats get along? If so what's your secret?
Not all cats will get along but eventually (months...) they will probably tolerate each other. Some cats though will never get along w/other cats.
In my experience most cats do become friends after a while but the depth of that friendship is variable. Often the depth of the friendship will increase slowly over time.
One thing i have done to ease and encourage friendships in cats that have already been together for a few days to a few weeks is put catnip on the actual cats, or on one of the cats. It's helped in a couple of cases. BUT these are cats that don't hate each other, they just don't seem to be establishing a 'friendship'. Of course this would be done under direct supervision.
In cats that actually hate each other (meaning one of the cats physically attacks the other in an effort to hurt the cat (versus cat play where biting still goes on but it's tamer biting and they understand when they have gone too far), I still might rub catnip on the weaker cat or both cats...but again only under direct supervision.
swapping scents through towel swap rubbing can also help in some cases.