Recommendations

From my experience with cats:

1. Food - Feed wet food, whether it is all natural or whether it is Fancy Feast or whatever you can afford. Don't switch food often for discounts though.

Hard food is generally not as good for cats because of processing limitations. If you need to leave food out available - obviously hard food serves. Some cats will wake you up in the middle of the night if they can't munch on something, and while it shows great dedication to do without sleep, I would leave some dry food for them. The Best cat food has
a minimum amount of additives and corn and preservatives
etc and has a high protein content. A really good food dry
if such exists really is Wellness Core, which
also has a somewhat small kibble. There are special formulations
for conditions etc such as Digestive Aid or the like.
When choosing a dry food always buy a minimal amount you can
throw away if your cat won't eat it or has an allergy to something
in it or the like.

2. Always provide fresh water. The filtered water bowls which
circulate water are quite good. Stay away from chlorinated water
if you can. Regardless make sure the water is CLEAN.

3. Don't clip claws, it opens them to infection, or you. The last place
they scratched was in the litter box. Unclipped claws have smooth
outer layers like onions. So clipped they stand a chance of a nastier
scratch if they ever do scratch you. It goes without saying that
declawing is cruel and can cause much more of a problem than it
ever solves.

4. If you want your cat to listen to you speak in a friendly voice,
and control your cat by rewards. A cat may learn the word NO,
but there is no such thing as effectively disciplining a cat.

5. A Maine Coon or long haired breed needs brushing or rarely
cleaning. Get them used to it when they are young if possible.

6. Keep your cat indoors. Besides dogs, diseases, other cats, cars
and any number of other hazards of the outdoors for cats
additional vaccinations must then be given. Also once you
"let them go out a little" they then tend to make a game of it
and charge the door when you come in. Do yourself a favor and
provide a desk by a window or a cat shelf by one, but keep them
indoors.

7. More to be added.....