To a horse, cat, or dog an outstretched hand with the fingers spread out to them means a paw with the claws spread out. To them that is very threatening and they will respond with either flight or fight especially if they do not know the person.
To a horse, cat, or dog an outstretched hand with the fingers made into a fist and held steady means a paw with the claws retracted and an invitation to come over and associate with the person.
Some cats like treats, and some may not care for them. You only need to give them 4 to 6 pieces. Try Temptations, or Greenies. One thing I do to let my cat know that I am the boss is I use the fact that in the wild the alpha animal of the pack eats first and then the other animals eat. In the evening I eat my dinner, and after I finish my dinner I give our cat 6 pieces of Temptations beef treats. I go out into the kitchen and get the Temptations treat bag and put 6 pieces in one of her dishes and carry the dish to the bathroom on the first floor. I put the cat in that bathroom and close the door and hide the dish somewhere. Then I let the cat out of the bathroom and she hunts for the treat and finds it. Everyday before I finish my dinner she sits and looks at me and waits for me to get her treat. It is something she looks forward to.
Also, some cats like catnip, and some do not care for it. If they like it you can spread some on the floor or one of those round cat toys with the ball that goes around and the cardboard center for scratching, and they will rub or roll in it and makes them drunk and feel good. They may play for a while after that and then go to sleep.
Be sure to change your cats water every day, and wash out the water bowl with a dish rag and a little soap every other day so no slime builds up on the surface of the bowl.
The stainless steel small water bowls with holders that large pet stores sell are a very good idea. Plastic has small cracks in the surface that lets stuff you can not see grow, and it can make your cat sick or cause skin problems around their mouth that the vet will charge you a lot to diagnose and tell you to buy the small stainless steel cat dishes at the pet store.