Notice their character traits. This is especially important with multiple animals. Most of the time, they have very different ways, likes, dislikes, and styles. They also respond differently to requests and affections.
Shed your inhibitions and simply lend your ear. Put aside any silly supernatural notions and realize that you genuinely and actively wish to hear from them. You won't actually start to hear them speak. But they are more mentally present and responsive than sometimes assumed.
Decipher their signs and signals. Stay calm and level with the animals, as though they can really hear what you're saying (in some way they can) when it's time to go to the vet or administer medication. They know something is up and feel nervous. Aloof energy increases the chances of mayhem. Contrary to common belief, cats can be trained. It is easier when the relationship begins when the animal is still young. A combination of positive reinforcement and non-physical messages of disappointment and/or urgency when the act is not carried out will work best.
Maintain consistency. Be consistent with the signals you use to identify and reward a request. That includes key words and phrases as well as visual cues. Most of the time, this practice brings the owner and animal into a closer, more mutually respectful relationship and eliminates some of the minuses of having an animal. Keep this in mind when considering giving a pet to an elder or family with small children.
Set the rules and limits. Give every pet rules, boundary limits, similar to their natural habitat where the mother rewards them with food for doing the right thing like waiting and being calm.
Be calm and assertive. You can control and claim the area. In addition, give your pet exercise (e.g. dog gets a walk). If kept at home all the time, they will have a bad behavior.