Hold out your hand and let the cat sniff it.
Then rub the back of the cat's ears.
Use both hands on the cat's ears.
When the cat starts enjoying your attention tickle it under the chin.
Hold onto the cat's tail, without pulling, allowing the cat to pull against you. They almost invariably lie down and become ameanable to belly-tickling. They then tend to gnash you with their teeth & scratch... But you've got'em.