1. Provide made-to-measure meals
Your happy little guinea pig should have access to water and hay at all times. You should also provide them with quality food that has been specially made for them. Not because they're picky eaters or like to pig out, of course. But, for example, it's good to give them food that contains vitamin C, because just like humans, guinea pigs' bodies do not produce it. They will certainly also be grateful if you give them a daily portion of tasty fresh vegetables.
2. Keep guinea pig cage clean
During the colder months, cleaning the cage weekly is okay, but once a week in summer may not be enough. If your guinea pig has a favorite place to do its business, it can be useful to clean it daily anyway. Also, remove vegetable and grain leftovers every day so they don't rot or mould.
3. Find a good place for the cageTaking care of your guinea pig also means putting the cage in a quiet place. Quiet is not the same as lonely! For example, do not place the cage in the garage (also because the exhaust fumes are harmful to their small lungs). Keep them away from drafts because it's disastrous for their health. It's also better to avoid bright sunlight.
4. Take care of teeth and nails
When guinea pigs live in a cage, their nails don't wear out naturally. That's why you have to cut them regularly. You can do this yourself with nail scissors. Or, if you're afraid of hurting your guinea pig, a good vet will be happy to do the job for you. Esthetician not recommended.
Their teeth also grow continuously. That is why hay is so important: it files off the teeth. Special wooden sticks can also help with this. Not toothpicks, of course. Those are for humans.