The guide consists of four basic steps: identifying a troll, doing a background research, labeling and ignoring.
As noted, trolls tend to comment longer than four lines and out of context, be openly aggressive and hostile, and make language errors.
Searching the Internet helps identify a troll (step 2). They usually post the same messages to different articles under different profiles.
After identifying a troll, it is preferable to label them correspondingly (step 3) for others to know and ignore such users in the future (step 4), since discussing with trolls makes them more credible and visible and indirectly suggests the significance or authenticity of their provocative statements.