I honestly think the only way to deal with child bullying is to remove the child from the situation. Either change schools, homeschool or unschool. Frankly I think a lot of bullying is a result of boredom, because when you think about it, schools really are prisons, and the inmates have underdeveloped brains and large lunch hours. There are also potentially dangerous areas in schools like toilets where there simply is no supervision. Also I read somewhere that the most dangerous places for the average person are public toilets and carparks - they are more dangerous at night and early morning, but they are dangerous because if there is no one else around you have no witnesses and are therefore easier to attack. In the real world people are advised to always stay alert - alert victims are harder to attack physically. Elevators and stairwells can also be dangerous.
Easiest way to stay safe - go to dangerous places in groups. Women are usually raped/kidnapped etc. when they go places on their own.
I seem to be getting off topic here, but doing things in groups may well be one way to counter bullying if the child cannot leave the school.
Also, if the child cannot leave the school I have two recommendations for dealing with verbal bullying.
Type 1 - Yelling - If someone yells at you they are counting on the fact that you will be embarrassed, ashamed, etc and will avoid them. Trying walking right up to them and staring directly at them. I have actually tried this and before I even got to my bully they ran the hell away! Also if you are CALM and confident and walk right up to them with no agenda but to act weirdly and put them off, staring at them and laughing at them can really work. Works best when your friends are not watching you because you will have to stop caring that you are looking really weird when you do this.
Type 2 - Whispering - If you overhear someone talking about you but they are talking so quietly that they think you can't hear them and you feel uncomfortable, or if they are deliberately using a stage whisper, the easiest way to confront them is to repeat what they are saying really loudly. I read that somewhere. It works because you are refusing to be uncomfortable therefore they have no power over you, plus rather than stewing about what you heard you are confronting the situation directly and therefore will feel better even if you get no result.
Ultimately these techniques may be too difficult for a child to master though and frankly I don't think they should have to be put in an environment where they have to deal with abuse from strangers but that's just my opinion.