In many senses, Hyderabad is the meeting ground between North and South India. The city has a culture that is distinct from the rest of Andhra Pradesh, showing Islamic influences and a courtly presence imparted from its period as the capital of the Nizamate. This is more evident in the old city. The new city resembles many provincial state capitals in India. Secunderabad is more cosmopolitan, as the Cantonment area is located in this part of the city.
Due to a recent influx of young men and women from various parts of the country for better job opportunities, Hyderabad's culture and attitudes have taken a turn towards "modernity". However, it is good to keep in mind that the city is still a deeply conservative place and to dress appropriately, especially in the old city.
Note that people have a very indifferent attitude towards time and a very laid back attitude.