The basics are - of course - food, water, shelter, attention, adequate exercise and stimulation, healthcare, and protection. There’s a huge amount of literature available on all of those topics — and so one more of the “basics” is learning enough about each of them to provide educated care for the animals you own. Rudimentary behavioral training is an essential as well. Having a pet who’s a good citizen in your household and in your neighborhood will make your life and your pet’s life easier and better.