Pre-requisites:
- Lubuntu
- Vim or Nano
For Lubuntu 12.04 or below
$ sudo vim /etc/lxdm/default.conf
And change the line:
autologin=yourusernamehere
For Lubuntu 12.10 and above
$ sudo vim /etc/lightdm/lightdm.conf
And then change this line:
autologin-user=yourusernamehere