8. Know the House Rules

At home, you may keep your Chihuahua with you on the loveseat, but don't expect your host to share your enthusiasm for welcoming your dog or cat on the furniture. Rules vary from household to household, and that's fine, as long as everyone knows what the rules are. To keep things cordial, don't wait until you break a taboo to understand what's expected; ask.
Even folks who have pets themselves may have very different ideas of how they share their homes with them. From using separate can openers for people food and dog food and only allowing animals in certain areas of a home to allowing the dog in the hot tub with you, the list of restrictions may be long or short, but whatever they are, you're in someone else's home, so respect them.
To be safe, ask questions before you assume anything:
Will there be restricted areas of the home?
Where will your pet be eating?
Is it allowed on the furniture?
Is it allowed in the yard?
Is it safe for your pet to interact with other household pets and children?
Where will it be sleeping?
The clearer the rules are from the beginning, the happier everyone will be.
For your own part, be candid about the potential problems, like your pet whining if it's separated from you overnight. Using this new information, it may be consigned to the garage, or even given the run of the guest bedroom to stay with you and keep the noise level down. Whatever the outcome, you'll be saving your host a sleepless night if you're honest. The same goes for potential accidents on the carpet, chewing, or territoriality near food. Armed with the facts, you can work together to come up with a strategy that suits everyone.