1. For Preselling Units, buy from reputable developer, and check out the agent to see if he/she is genuinely authorized to sell the particular unit. For secondhand units, check if the seller has clean title to the unit. Ask for a certified true copy of title, and make sure there is no debt attached to it, or someone else has claims on it.
2. Ask questions, and get answers in writing. e.g. for preselling units, when will it be completed? any compensation if completion is delayed?
3. Beware of the costs involved, in addition to the selling price of the property.
The buyer has to pay:
Documentary stamp duty (1.5%) for Bureau of Internal Revenue
Transfer tax (0.75%) for Land Registration Authority
Title registration fee (0.25%) for the local government's treasurer
Information Technology fee (a few thousand pesos)
these are paid to government authorities. In addition, you as the buyer may have to pay a fee to hire an agent to process the documents if you do not want to spend time in the government offices, or wait months for documents to be released. Documents have to be notarized, the cost of which depends on the notary public that you use. Normally 0.1% of the selling price should be more than sufficient.
The seller has to shoulder the Capital Gains Tax (Bureau of Internal Revenue), which is 6% of selling price.
4. Before making final payment, check that the seller has paid all the real estate taxes and condominium association dues.