Reward and punishment (occasionally) are the key to a good relationship.

Dear George,
I have adopted a new human family - male, female, and two human kittens about half grown and therefore a sensible age. You know my background growing up which turned me into a growling, biting and scratching adolescent.
This is my third home - first the bad one, then with Celia, and now this. Of course, I can adapt. I don't miss Celia at all though I miss the games I had with Toby. Within two days, I was sitting on the male owner's lap and (good news) he was keeping his hands away from interfering with my grooming routine!
So these are sensible humans. I have taught the children that if I sit up and beg or jump over a stick, they must give me food. What else should I do?
Yours
Tommy.

Dear Tommy,
Reward and punishment are the basis of a good cat-human relationship. In the first month of your new home, you should at all costs avoid punishment. This is the time to reward them with cute looks, lots of purring, rubbing and making them feel loved. As Barnum said: "You gotta get the suckers into the tent." These humans need all the reassurance and kindness you can give them so that they form a deep bond with you.
After the first month you can lay down a few boundaries - no interference while I am grooming: no human thrashing about the bed I allow you to share: if you use your hands to play with me you must expect to be nipped; etc. These cat rules will vary from individual to individual and in the second month you should be training them to obey by very small nips. And don't forget to purr when they behave well.
By month three, all four should be trained into proper cat servants. The key is good timing and consistency. Good luck.
Yours
George.
PS. If you need to bite, you haven't made your rules clear to these dumb humans.