Difficulty: Moderately Challenging
Step1
Claim some territory. You can actually claim very real, accessible land which technically belongs to other nations and governments. Many nations will leave you alone as long as you don't constitute a threat.
Step2
Create a constitution or other articles of government. Many micronations have a particularly libertarian bent, but the beauty of founding your own nation is that you have free reign to make whatever proclamations you wish.
Step3
Establish a population. This may only include one person, or perhaps even a pet. But if you would like to bolster your population, you can simply streamline your naturilization process, accepting all applicants from around the world as full-fledged citizens.
Step4
Invent your own currency. This money could be traditionally printed, but it could also include ready-made physical objects like sheep or seashells.
Step5
Announce holidays. January 8th is a common holiday for many micronations, and celebrated as Emperor Norton Day.
Step6
Nurture relations with other governments. Other micronations might be the most agreeable to diplomacy, but if you've nothing to lose, try opening diplomatic channels with heavy hitters such as China or Latvia.