CCTV consist of several essential elements: 

The Camera: 
There is a huge choice of camera to be had, you will have to ask yourself several questions to determine what type of camera you will need: 

• Where should I site it? Vandal proof or not?
  
• What is it looking at? Bright light or complete darkness?
  
• What do I want to see? Short range or long range?
  
• Should people be able to see it or should I keep it discreet?
  

Transmission: 
How do I get the picture back to where I can see it? Wired or Wireless? 

Monitoring: 
How do I watch it? 
Do I want to watch it all the time? 
Can I watch it on my TV? 
Can I watch the cameras on my Laptop or phone when I am away from home?

Recording: 
Do I want to record the images? How long do I need to?
How good will they be? Will I be able to enhance them?
How easy is it to give images to the Police if I need too?