Real estate knowledge (as available online) only gives a hint, while the real insight are only possible when you get into the game!
Its like you can see and search your dress and vegetables on an online store, unless you see them in normal resolution with your eyes, touch to feel their stuff/freshness and compare with the other available on the shelf, you never know what you are dealing with.
To me its a combination of Online information + site visits + individual's capability to judge + information from right people + so many other factors that come into play to get accurate and balanced information about any property. There is a difference between one time purchase or be an ambitious one who like to keep rotating the stuff in his/her hand at the right time (considering the case of a common man)
Long discussion cut short, its about experience that requires time. On a technical side, the basic checks can be:
1. Legal and Development Aspects
- Land disputed or clear of any litigation
- Access and Available amenities
2. Investment Perspective
- Past growth and future of the land that one is interested in
- Market value of the land and price justification as per the Market Trend.
- Have the value got appreciated too quickly in recent past and currently on a still.
3. Land Terrain
- Plot level or in depression
- Plot level or being filled
- Plot not too close to some Canyon (khai or gahrai) or close to the high tension electrical wires.
These are a few, that I would like to see (ideally), hopefully other fellow forumers can add more valuable insights than these.