For maximum effect, blackmaiing your enemies requires finesse, not force. A gentle touch can mean the difference between a well-timed blackmail demand and an international incident.
Learn how to craft the perfect blackmail letter
Blackmailing in high-pressure situations
But, of course, there's always the option to just go for broke and send a strongly worded email instead. The results may vary, but it's a great way to clear your head and practice your writing skills.
Email alternatives to blackmail