How to customise LightDM Login Screen in Ubuntu to remove Guest Account, Remote Login, white dots, sound effect, and to change the background

Terminal Commands
sudo apt-get install dconf-tools (for Ubuntu 13.04 and before)
sudo apt-get install dconf-editor (for Ubuntu 13.10 onwards)
sudo cp /etc/lightdm/lightdm.conf /etc/lightdm/lightdm.conf.old
sudo /usr/lib/lightdm/lightdm-set-defaults

sudo xhost +SI:localuser:lightdm
sudo su lightdm -s /bin/bash
dconf-editor
exit
Or use gsettings for Terminal method of editing dconf
gsettings set com.canonical.unity-greeter

Wallpapers:
http://imgur.com/5vNJyO0
http://imgur.com/7tuDwDv
http://imgur.com/PS1Nsu9