How can bullying be stopped?

I figure the first step is identifying who they are.

With animals it is relatively easy to determine which is typically the predator and which is often prey by looking at their characteristic features. Predators usually have eyes in the front while prey have eyes that look to the sides. Predators have better long distance vision with a narrow field of view, while prey can often see almost 300 degrees without moving. Study other characteristics like claws, teeth shape, jaws, bone structure and you can tell who is the hunter and who is the hunted.
Let’s carry this to humans. Are there characteristics that identify the bully and the bullied? Can one day of videorecording activities on the playground, in the class room, on the bus, in the hallways, identify potential bullies? Do bullies make up 1% of a class or is it 25%? Can an honest, anonymous survey of students and teachers identify potential or actual bullies?
Once they are identified, are there social changes we can teach such as:
– Encouraging bystanders to record acts of bullying so it can be used as evidence in criminal prosecution.
– Teaching students if you date a bully, you will likely be bullied later.
– Step in if you can or dial 911.
– Teach that people are judged by the company they keep.
Are there other examples?