Pets should wear ID tags with your contact info in case you get separated in a crowd.
Leash train your pet and bring a sturdy leash to maintain control in busy areas.
Scope out a pet relief area beforehand so your pet has a potty spot when needed.
Bring a pet first aid kit to treat minor injuries or issues on-site if needed.
Bring plenty of water and a travel bowl to ensure your pet stays hydrated.
Allow your pet to rest in shaded areas and cool down as needed to prevent overheating.
Consider a Thundershirt or calming treats if your pet has event anxiety.