I guess no one will share you that information here. We are not here to teach other to do something that will heart other.

But there are so many articles out there discussing about this subject. Just google how to do negative SEO

This forum isn't for things like that.. Don't make these types of thread, it's unethical..

1) Go to the digital point forum
2) follow all the advice given their

Thats pretty much guaranteed to tank any site =D

please dont make such threads..its unethical..

Are you really planning to get on somebody or you asked your question in the wrong way.

You can not penalize somebody's site unless it's yours.

Google uses a number of factors before it hits a site.

The famous Panda and Penguin where all about crap content and over optimization respectively, as you can see it's all an On-site affair which has to be capped with off-site before Google crown you Judas.

Thats not really fair to do that to someone elses website/business. Losing them income and ruin hard work they have done, that doesnt only affect the person that affects that persons family too! Think about Karma before doing something like that.