When I used to have my turtles, I'd just sit on my bed and stare at them swimming in their tank. A few times I was "naughty" and took them out of their tank, put them down on some newspapers, observed to see how fast they could walk on dry land. They're very fast. Sometimes I would nuzzle the tops of their heads with a finger after I fed them, but I stopped doing that once I read that they were solitary creatures who preferred not to be touched. Mostly I'd just make facial expressions at them, but not expecting to understand. I talked to them occasionally. The most reaction I get out of them is when I would pull out my guitar or sing near their tank. They'd suddenly climb up on their dock and just sit there, heads in the direction of the music. They'd also climb up whenever they saw the TV on. I experimented putting my phone screen up to the glass, and a few times even showed them photos of themselves on my camera to see how they'd react, if at all.
With my hermit crabs, I don't remember interacting much with them. I'd just observe them, and pick them up whenever they had to transfer tanks to have their previous cleaned. Same with my frog.
For a short time we had a black and white hamster clichely named Oreo (we bought him from another owner, and he was already quite old by then), but he stayed in my sisters' room so I got to interact and watch him considerably less. Daily we'd take him out of his cage, into the bathroom (closing the door behind, so he wouldn't run out and get lost), and let him roam around freely. He'd crawl all over us and the furniture, roll around in his exercise ball, and we'd feed him little treats by hand. Such a cutie pie. I really wish I had a furry pet again. I want a rat really badly, but I'm in no circumstance to get one.
Soft, slow voice(I use a dark voice when she's doing something bad and she usually stops doing what she was doing), sounds, using special phrases/sounds that she associates with different things(playing, food, brushing fur-when I tap the comb she comes and stands next to my leg, going outside etc), meowing back/listen to which type of meow she's making, blinking/squinting with my eyes, yawning, buffing my head on her head/side-of-butt, pointing and saying "there"(and she'll know that it's an insect), general petting, letting her lick my arm(it makes her happy) etc
With enough concentration, I can use my telepathic powers for a proper conversation. Sometimes I have to place my hand on his head for a better connection. He doesn't like when I get melancholic and bring up philosophical topics such as: the meaning of life, the human-universe armony, the ethernal nature of the human soul. He always finds a way to shift back to his favourite topics: sweet carrots, juicy alfalfa, rabbit related sexual fantasies :cig . He is a cheeky one. :um