The first and most important step in avoiding any health complications is to have Vet visits all checked up! Make sure your pets are all caught up with their shots and vaccines. Talking to the doctor in regards of any extra treatments or follow ups is also important for your dog's health.
In terms of dealing with the heat - which is a constant and challenging situation here in Florida - keeping up with their grooming and trimming (for long hair furry friends which are the ones who suffer the most) hear cleanings, nail clipping and baths. This way you can prevent overheating on days that are absolutely and extremely hot.
Hydration is key! just like us humans; pets need to stay hydrated, for every activity under the sun keep a bowl of clean water, or if you're taking your dog to a park; often you'll find water fountains in there, but to ensure you're prepared for the ride take a big bottle of clean water - you can put some ice cubes to keep it cooler and not as hot as the weather.
If your dog is exposed to the heat for a long periods try checking the paws regularly, keep them clean and them apply cool (not cold) water on your dog's paw, this will help prevent overheating and exhaustion. Don't leave your pet in the car! treat them as your baby, even if is only for a couple of minutes, keep in mind the car can overheat even when the windows down.
These are the most simple and recommended tips, for new owners; get to know your pet's behavior - observe the difference when they are inside the house and when they are exposed to the heat, that way you know if there's something that could be going wrong and you're able to take early decisions which could save your dog's life.
Lastly, pets are a big responsibility to ensure their well-being take care of them. Plan ahead of time for a day in the park of if you're keeping them in the patio. These tips will help you to greatly increase the comfort and health of your pet.