Oh man, I feel like that's asking someone the best way to rob a bank or something... But it's not a bad question--I think there are different kinds of believers in conspiracy theories, but all theories are satisfying some basic psychological need, something that makes the believers feel good about themselves or lets them feel safe or comforted about their worldview, or lets them indulge in problematic views that are otherwise not acceptable in mainstream culture. So I'd work backwards from that? Like what psychological need do you want to tap into? From there, you'd want something that could easily accommodate conflicting evidence, so even things that "disproved" your theory could in fact be made to "prove" it. Lastly, you need something that holds out vague promises but never actually needs to deliver on those promises... like a Nostradamus prediction or an astrology reading or a Q drop, something that allows people to believe it's true even if you don't ever actually prove anything....

A lot! For one, during the colonial period and the American Revolution, there were plenty of conspiracy theories that the British and/or the French (depending on who you talked to) were secretly infiltrating American politics and perverting events. But probably the most commonly held conspiracy theory that has more or less (but not entirely) fallen by the wayside is the fear of Catholics... This was widespread by American Protestants, who felt that Catholics were taking orders directly from the Pope or their priests and that they were infiltrating American culture with an eye towards domination. This persisted well into the twentieth century (JFK had to give a speech saying he wouldn't listen to the Pope if elected president!), though within the last 50 years Protestants on the American right have aligned with Catholics over social issues (abortion, school prayer, etc.) and have largely abandoned that conspiracy theory. (This is something I follow a great deal in my forthcoming book, Under the Eye of Power, that follows the history of American conspiracy theories surrounding secret societies.)

This is a great question--because The New Chronology is popular in Russia particularly, and appeals to a specific set of nationalist ideas about the Russian empire, it maybe makes sense that the conspiracy theory would highlight a belief that ethnic Russians--blond, blue-eyed Slavs--were at the heart of all civilization. The Russian Empire is a bit different, historically, from others that we may be more familiar with (say, the British or American empires), because the idea of a Russian empire is inherently multi-ethnic in a way that those in the west aren't. While the British conceived of their empire as one where they were ethnically and racially superior to those they colonized and subjugated, the Russian Empire was always deliberately multi-ethnic, with ethnic Russians just a kind of "first among equals," so to speak (assume that a lot of what I'm saying here is in scare quotes--I'm doing my best to relay what I believe others think and obviously am not endorsing any particular racist or colonial logic myself!). The New Chronology, which is more explicitly racist in its positing that ethnic Russians are at the heart of all culture and civilization, is thus a break from the traditional ways that the Russian Empire has been conceived, and is what happens when you have an empire (in this case, the Soviet Union) fall apart and leave behind only wreckage, with people clinging to increasingly extreme and problematic theories to make sense of what's happening.

Oh, that's a tricky one! In general, my feeling is that the bigger a conspiracy theory is, the harder it is to prove and thus the less likely it is to be true. So, re: Area 51, etc., I have a hard time with that because it seems like there has to be a whole lot of people--janitorial staff, busboys, cooks, administrative assistants--keeping that place running who have no incentive to keep their mouths shut. The bigger the thing is, the more people it takes, the more likely there is to be leaks. So, personally, I find the most convincing stories are the ones that are the most nebulous, the most vague, the ones that don't really posit a whole worked out theory so much as just some unexplained thing. In The Unidentified, my last book, I tried to do as much of a survey of postwar UFO and alien sightings as I could, and the one that I came back to time and time again without a clear explanation is the Socorro, NM sighting by Lonnie Zamora. Precisely because it was weird and inexplicable....

A belief that is based upon shadow evidence, not direct evidence with a pinch of a similar incident or organization whose truth has been revealed.

An example; the government is spreading chem trails. No direct evidence exists that this is happening. However, the CIA did disburse a specific bacteria over an American city once to see if it was effective by being aerosolized.

https://en.m.wikipedia.org/wiki/Operation_Sea-Spray

I think it means any idea not coming from corporate media or official government.

Mr. Dickey does a great job explaining where this idea came from in his book The Unidentified. I recommend it, if you’re interested in lost colonies/cities like Atlantis, Lemuria, etc…