In Behind the Beautiful Forevers, why do the Annawadians seek Asha's counsel? How does she decide whom she will assist?

The Annawadians seeks Asha's counsel because she's considered one of the "higher" people in the micro world of the under city. People instinctively look up to her because she has greater authority than anyone else in the slums. She is fast in the process of becoming Annawadi's undisputed "slumlord" with access to the kind of power, money, and respect that few others in this area could ever dream of.
The downside of being a slumlord, however, is that one becomes caught up in the corruption that blights the city, especially slums like Annawadia. Asha carefully picks and chooses which people to give loans to depending on the size of the bribe she can expect to receive from them. If the bribe isn't big enough, she tells people to go away and pray to the gods. This is her way of telling them to come back with a better offer.