How to tell if a neighbourhood will appreciate before everyone else figures it out
1. Buy after the metro is sanctioned not after it opens
By the time the line is running you've already missed it. Hinjewadi corridor in Pune saw 10--25% annual appreciation while it was still being built.
2. Watch where the next IT campus is going
Companies announce a campus in cheap undeveloped land and thousands of employees show up. All of them need housing nearby. Demand spikes, supply lags and so the prices rise. Whitefield and Gachibowli are the proof as both were on the edge of nowhere until the campuses came.
3. Read the city's Master Plan it's free
BBMP, MMRDA, DDA all publish development plans. When an area gets rezoned from low density to mixed use prices follow in 2-3 years. Panvel and Kharghar were in MMRDA's plans years before they blew up.
4. Spillover is the simplest signal
When an area becomes too expensive, people don't leave the city they move next door. When Koramangala priced out HSR Layout filled up. And when Bandra priced out Khar filled up. The pattern is always the same. Find the neighbourhood everyone wants but can't afford anymore then buy in the one right next to it with no geographic barrier. That's your 5 year bet.
What to avoid: Any area where one developer controls 70%+ of supply. Your resale competes directly with their new launches and you will lose.