I can immediately jump the opportunity to tell you about places to see in Prague, Paris or Roma. I can tell you places to avoid in Vienna and where best to get your schnitzel but it has been a while since anyone has come to me for travel tips to my own country.
My first warning is always do not drink the water from the tap and in the same logic, no ice in your drinks! Watch out for pick pockets and do not be too trustful of strangers. Typical travel tip I would give to anyone traveling anywhere, as a matter of fact. And then seriously - spend a few more bucks to get yourself into a 4 or 5 star hotel because the money you save will not be worth the headache you will get nor the security that you risk staying in a cheap hotel. Not in Manila, anyway.
Filipino food is saucy and flavorful. Enjoy some sour soup (sinigang in its many forms - with prok ribs or fish or shrimps), grilled fresh fish that is cottony and lightly salted, kare-kare (ox tail soup cooked with peanut sauce), adobo (chicken or pork cooked in vinegar and soy sauce), the local version of ceviche and ginataan (anything that is cooked in coconut milk). Filipinos are meat eaters so vegetarian feasts are rare and few but you will still find them if you ask for help from the restaurant staff. Vegetables are more 'sahog' or ingredients that are added onto the meal, not the main meal. For me anyway, who grew up detesting any variety of vegetables. You can go to the malls (and there are plenty) and enjoy different kinds of cuisine. In December I discovered the tapas bar at the Bonifacio Global City and also enjoyed their paella and callos. Filipino food is generally greasy and salty so take heed. Always remind the people taking your order to take it easy on the salt.
The road network has very much improved in the last 12 years since I last called Manila home. Although during rush hour the main thoroughfares still transform into major parking lots, it helps to be familiar with the road systems to find small roads that can take you from point A to point B without breaking a sweat. The country continues to expand its road network and I was impressed that there are now more ways to get to Tagaytay City from Manila than just the Imus Highway of many years ago. It doesn't help, of course that Tagaytay City continues to lack the facilities to accomodate the increasing volume of day trippers but then I will also remind tourists to avoid the mountain view attraction in the weekends. Stay away from the malls in the weekends as well - unless you don't mind getting yourself a migraine with the overcrowded locations. Restaurants will be full, movie houses will be crowded and parking will be a pain.