How to Customize Login Screen in Ubuntu

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