So you think you’re a natural-born filmmaker who was put on this earth to direct movies? Join the club, pal.

With the advent of cheap cameras, the Internet and online video-sharing sites like YouTube and BitTorrent, practically everybody is an aspiring Spielberg or Fellini these days.

But making a movie, be it a five-minute short or a two-hour feature, takes more than vision. In his witty and addictively readable book “The Reel Truth: Everything You Didn’t Know You Need to Know About Making an Independent Film” (Faber & Faber, $25), author Reed Martin provides 500 pages of how-to advice for would-be De Palmas — everything from financing to casting, scoring to marketing — and backs it up with cautionary anecdotes and tips from famous directors.

We spoke to Martin, 39, about the book and his motivations for writing it.

Q: When the modern-day independent film movement started in the 1990s, everyone went from wanting to write the Great American Novel to wanting to write the Great American Screenplay. Does that still hold true today?

A: It does, although there’s been a generational shift. Back then, everybody wanted to be Quentin Tarantino or Miranda July. After that, everybody was starting Web sites, wanting to be the next Sergey Brin and Larry Page (founders of Google). Now it seems everyone is creating iPhone apps.

And for people who yearn to tell stories, everybody wants to direct the Great American Movie now. It’s gone beyond the writing, because a lot of people don’t have the patience to sit down and write a novel or a 120-page screenplay. But they do want to direct a film.

Q: They also feel that they know how to do it because of the accessibility of filmmaking tools nowadays.

A: We’re living in an indie film nation right now. Every laptop computer ships from the factory with built-in video editing software. Just the fact you have this free software available has really opened it up for people. Not only can they shoot video with their handheld pocket digital cameras or cellphones, but now they have the tools to put it together and make something sophisticated.

Q: What is the biggest mistake aspiring filmmakers make when they decide to direct their first film?

A: The biggest one is that people don’t copyright their screenplays. The most important part of any independent film is really the story and the screenplay. A lot of people mistakenly think that by mailing a copy to themselves and not opening the envelope, that somehow triggers a copyright registration called Poor Man’s Copyright. But … there’s no such thing as Poor Man’s Copyright. It’s a myth. People really have to take the time and spend the $45 to register their screenplays with the Library of Congress.

Q: The accessibility of filmmaking equipment has been a particular boon to the documentary field.

A: What’s exciting in the documentary realm right now is that there’s a new opportunity for documentary makers to become filmmakers. The first evidence of this is Seth Gordon’s “The King of Kong: A Fistful of Quarters,” which is a film I totally love. One of the things he did was to acquire the life rights of the people he was interviewing for the film. As a result, he was able to sell the remake rights to the documentary when it was picked up to be turned as a feature film, which I’ve heard might star Greg Kinnear and Tom Cruise.

So if you follow a traditional three-act structure in your documentary and follow a dramatic narrative, you can possibly make a big payday from selling the remake rights.

Q: You learned a lot of the lessons in your book the hard way, didn’t you?

A: A lot of people who want to make films come across an interval — some down time between jobs, a severance package, some money their grandfather bequeathed them — and they decide “OK, I’m going to go for it.”

But the problem of making your film in this compressed time is that you tend to cut a lot of corners. You start thinking, “It doesn’t matter if I have to pay triple or quadruple for this, because it’s now or never.” You feel that if you don’t seize the opportunity, you’ll miss your window, and so you fall into this anything-goes trap. As a result, the cost of what is supposed to be a low-budget independent film quadruples or quintuples.

In my case, I had a great idea for a short film I wanted to sell as a commercial to Coca-Cola. So I started making this short. The costs just kept going up and up. For a two-minute short film I ended up spending $30,000. And along the way, every possible thing that could have gone wrong, went wrong. It was unbelievable.

When I decided to write the book, I turned to the pros, because I figured no one was going to believe it if it was just me, a civilian, saying, “Here’s what you have to look out for.” And the shocking thing was that all these famous directors everybody knows, like Danny Boyle or Darren Aronofsky or Christopher Nolan, were all like, “Oh, yeah, the same thing happened to me.” In writing the book, I discovered that meteoric success and blazing failure are a hair’s breadth apart. The only thing that prevents a lot of people from becoming successes is not avoiding some incredibly stupid and avoidable mistakes.

Q: Did writing the book whet your appetite for giving filmmaking another shot?

A: It has, because now I know what to avoid and what to do differently. More importantly, it has also shown me that even though there are fewer theatrical independent distributors nowadays, there have never been more opportunities to get your work seen by people. Jet Blue has this thing now where you can credit card swipe every individual screen below the headrest on the seat in front of you. That’s an opportunity for content providers to monetize video content. With Internet access on planes, you have people on a five-hour flight who can access BitTorrent on their laptops, which is now redesigned as a pay service.

Before, you’d enter your film in a festival and hope it got selected, screen it for a couple of hundred people, and then go home with nothing to show for it. But now anyone can get their films out on YouTube in front of people, and if it’s something that is professional and can really tell a story, and it hasn’t been felled by the same mistakes that felled some of the biggest names in the industry, they can take it to the next level and become the shining stars of tomorrow.