Following are the steps to install Ubuntu Nvidia drivers and activating it.

sudo apt-get install linux-headers-$(uname -r)
sudo apt-get install nvidia-310
sudo apt-get install nvidia-313-updates
sudo apt-get install nvidia-settings

Once the instllation of the above mentioned packages are successful, run

sudo nvidia-xconfig

This will create the /etc/X11/xorg.conf file

Now, do

sudo software-properties-gtk

Which will open up a window like this


Select the latest driver name from the list and then do

sudo reboot

That's it :)