Metro Manila is a cosmopolitan city, and like all big cities you need to be sensible, but it is generally a very safe destination.
The Philippines is a tropical country, and Metro Manila can get pretty warm quick. Do bring a sunblock with a high UVF rating and pack light clothes. Bring comfortable shoes and sandals, bring shirts and polos with light fabrics, and do pack some shorts. Bring slacks and a light jacket should you want to go to places with a more rigid dress code, like high-end restaurants and clubs.
The main gateway to Metro Manila is the Ninoy Aquino International Airport (NAIA), which is divided into three main buildings (NAIA 1, 2, and 3). NAIA 1 and 2 are roughly 30 minutes away from the Mall of Asia Arena, and NAIA 3 is about 40 minutes, taking traffic into account. Most international flights go through NAIA 1, while a select few airlines go through NAIA 3. NAIA 2 exclusively services Philippine Airlines, the Philippines’ national carrier.
Regular taxis (White) are the easiest and cheapest option to take when travelling within Metro Manila. That said, most Hotel cars are also very reasonably priced by global standards and are generally a better quality of vehicle. The Flag down rate for the local white taxis is Php30 ($0.64 US) and the meter climbs in increments of Php3.50 ($0.07 US). Ride-sharing services such as Uber and Grab are also available.
Metro Manila has an extensive if rather helter-skelter public transportation system. The Metro Rail Transit (MRT) - Light Rail Transit (LRT) system allows visitors to travel to key locations in Manila, as well its major cities such as Quezon City, Makati, and Pasig. However, using the MRT/LRT is a bit challenging as the systems are currently being overhauled. Visitors may also take the buses for longer trips, and the famous Philippine Jeepneys and Tricycles for shorter trips.
In terms of required immunization, whilst not compulsory, the WHO recommends Dengue and Malaria shots for travel to the Philippines if you intend to travel outside of Metropolitan areas.