sticking a finger out for them to sniff and rub against is another good one. hypothesis is that it's not dissimilar from the way cats bump noses and rub their scent off on each other

I also like making myself small and crouching and being as still as possible. I've befriended many skittish feline this way

I really like cats :)

I do all that plus I growl, hiss, rub my nose/cheeks against theirs, lick and groom their neck and forehead area just like cats. I imitate a dozen more cat behaviours.

I'm blessed with a lot of stray cats and slow-blinking alone helped me become friends with the most feral and aggressive tomcats here.