I am using a USB dongle (Tata Photon+ and Reliance Netconnect) for Internet and I want to share it over WiFi so that I can use it for my WiFi Tablet. I mean to turn my Laptop into a HotSpot so that I can use internet on my other devices. The option in Network settings called Use as a Hotspot is not meant for a USB-modem and its not working. I am asking this because I can't find a working solution.
You can try to use special Software to start a Hotspot. The easiest solution for myself is ap-hotspot.
A broader description of it can be found under the following link. http://www.webupd8.org/2013/06/how-to-set-up-wireless-hotspot-access.html
It installs Hostapd on your Laptop, directly via a PPA. After that just start it with the following command.
sudo ap-hotspot start
and also restart or stop it this way.