Firstly, please check out whether there are Exophones available in your circle.
If it's not, you could choose to take a number closest to your circle, say, if you are from Jaipur, you could get a Delhi-based number, and start using it right away.
However, if you do that, you will incur additional STD cost for your diverts and calls.
Please feel free to write to us at hello@exotel.in for any questions