It's best to walk around Naples since many of the city's attractions are within walking distance. Additionally, you can use local buses or taxis to get to your destinations quickly. Be aware of pickpockets in crowded areas, especially on public transportation. Expect to pay €1-2 for a bus ride and €10-15 for a taxi ride within the city limits.
If you have more time, you can visit the nearby Mount Vesuvius, Pompeii, or the Amalfi coast. For a shorter trip, consider focusing on one or two attractions and giving them more time to explore. Be aware that most shops and restaurants in Naples close for a few hours in the afternoon for a siesta, so plan accordingly. In addition, make sure you try the local seafood and pastries, which are known for their exceptional taste.