Do take the time to smile. Filipinos like to say hi, and they appreciate it when visitors reciprocate. Handshakes are the usual way to greet people, but "beso-beso" or cheek bussing is also commonly done, especially among ladies.
Do come in appropriate clothes when the occasion calls. Although the Philippines is a walkable country, not all places would welcome you in your flip-flops and shorts. Churches, government institutions and some restaurants require proper attire. Besides, if you come well dressed, Filipinos will admire you, and it's always fun to dress up!
Don't forget to laugh. Laughter is used very frequently in the Philippines: to break tension, to relieve moments of awkwardness, and to put people at ease. On the rare occasion that laughter is at someone's expense, it is usually done good-naturedly. A good sense of humor is definitely an asset in the Philippines.
Don't lose your temper. It's easier to get Filipinos on your side if you approach situations in a calm and composed manner. Filipinos are more willing to help if you don't embarrass them in public.
Do recognize that Filipinos tend to be indirect. Even if they mean to refuse, they will avoid actually using the word "No" in conversations, and instead will use other ways to get their message across.
Do show respect to anyone regardless of their social class or age. Saying "sorry" and "excuse me" is appreciated. In Philippine culture, the elderly are given particular respect. Using the proper words (such as the polite "po" and "opo" when speaking to elders) is a sure way of endearing yourself to Filipinos.
Although tipping is not institutionalized as a custom, do leave something on the table.