As per the given details of a webmaster, a few steps are being followed here for using this strategy of negative SEO.
Step - 1.) On the very first attempt in first month, he prescribed to post guest blogs using broken english which should be worse one a first glance.
Step - 2.) In the second month, try to post few more guest blogs with the same broken English with some links of the site you are willing to harm.
Step - 3.) Increase the quantity of guest blogs in the third month with some more broken English and increase the forum links as well.
If the site has not tanked yet, hit it with a huge traffic of inbound links all at once and repeat the same until you see that the site you are aiming at will hit soon. Eventually, they won't be able to find out the reason behind this sudden sink due to the "Penalty Mentality" that Google has declared to run with. Add on to this, it is a very affordable process which costs very little and will not consume much time.
To know more about it, you can visit http://www.simpliti.com.