There three basic things which would help in the success of the call centers.
a)A good Telecommunication Setup.
b)Good source of Agents
c)Good Marketing Plan with Infrastructure.
So Mohsin, anyone who has to start a call centre would have to know whether he can able to afford all this three.(This is applicable even to serve the local market).
Once you have good infrastructure inplace, then starts the marketing, because if your expectations are clients from USA, they would definitely like to know the facility that you have.
There are lot more details, involving the selection of the technology, selection of the systems, selection of the software, which plays additional part in the successful and profitable operation of a call center.
Intially it is better to go along with WebBased Call Center, which would fetch much lesser revenues compared to Voice based call centers, but which have much lesser risk. Your infrastructure should be capable to handle both WebBased and Telephonic based Call centers.
And in Telephonic Based Call Centers, it is always advisable to initially go with Outgoing calls and probably after an year or so, once we are confident of handling calls, we can get into Incoming Calls which is very Lucrative.
Hope this details help you.