1. Make a title that tells what the problem is. "Trolling in Katganistan is Great! Thread" is helpful. [Report] by itself is not. Vague [Report]Problem.... or [Report]This breaks so many rules.... is not.
2. Tell us exactly what the problem is in your post. "So and so is bothering me!" is too vague to be useful. Linking to the whole thread is not useful. "In these three linked posts, Katganistan has called me a buttered bun" -- better.
3. Tell us who is involved. "Some guy is being mean!" is not very useful. "Katganistan is spamming our thread, and we suspect that Puppet1, Puppet2, and HaHaYouCan'tProveIt'sME are also their puppets" is better.
4. LINK to the evidence. Right click on the rectangular page link at the top left the forum post. Paste that URL into your report.
Thanks.