In the UK, the arrival of coffee shops, such as Starbucks, is seen as one of the first signs of an area's gentrification.
The other thing that I'd suggest looking for is artists. The general cycle is:
- Artists find a town or suburb that's cheap and run down, but has character. They start to move in.
- Things improve, and the area becomes increasingly hip and gentrified.
- Richer people, looking for a cool place to live being to move in. This drives up prices, which in turn displaces the artists and who migrate elsewhere.
Somewhere like Fitzroy in Melbourne is probably as step 3, with the arts community moving out to Brunswick. Or that's the impression I got a couple of years back when I was last there.
A couple of examples from the UK: The area around Hoxton and Shoreditch went through this process some years back. One of my brother's friends sold a house on Hoxton Square to a boxer, it might have been Prince Naseem, for a substantial profit.
What's been happening more recently is that tech companies have been moving here, and there's a general sense in which London's centre of gravity is moving Eastwards. That might be because the West End is doing the whole superprime thing, and unaffordable to anyone who's not a billionaire or has a source of dubious wealth, or the City is expanding more in Canary Wharf. But if you bought property there ten or fifteen years ago you'd be laughing now.
Similarly in Brighton and Hove. In the mid-nineties it was a bit of a dive, and consequently cheap. I know of a few people who bought houses there on credit cards.
By 2000 it felt as though it was populated by artists and pop-stars. I was there in the early noughties, and it felt like living in an episode of the sitcom Spaced.
I moved out in 2003, and went back there for the first time last year. It's definitely lost a bit of its edge since then. I suspect that the twenty and thirty-something hipsters I knew have settled down and had kids. It's now more designer than quirky.
In the meantime the arts colony has shifted to Hastings...