By John McCrank

NEW YORK (Reuters) - Kevin Smith says he has learned a lot of tough lessons in the two decades since breaking into the film industry with his indie hit "Clerks," and now he wants to pass them on.

"Tough Sh*t: Life Advice From a Fat, Lazy Slob Who Did Good," Smith's fourth book, hits the shelves on Tuesday in the United States. In it, Smith focuses mainly on the highs and lows of the last five years of his career. He also talks about why he intends to retire from directing movies and other future plans.

"Film is one of the only art forms where you're like, 'I want to express something, give me $20 million and Ben Affleck in order to do it.' I've done that," he told Reuters.

Smith, 41, made "Clerks" for under $30,000 at the local convenience store where he worked. The movie went on to win awards, was acquired for distribution by Miramax Films and pulled in over $3 million in theaters.

Since then, the New Jersey-born Smith has written and directed films including "Dogma," "Chasing Amy," and "Zach and Miri Make a Porno." Some were critically acclaimed, while others, like "Mall Rats," and "Jersey Girl," were panned.

He vowed he is working on only one more live-action feature: "Hit Somebody," a story that follows the life of a Canadian hockey player from 1950 to 1980. After that, he plans to focus mainly on podcasting and his Internet radio station, SModcast.

"Podcasting is the democratization of entertainment. It really blurs the line between the entertainer and the entertained," he said.

Smith has built a large online following, and 'Tough Sh*t' started as a number of tweet responses to questions from some of his more than 2 million Twitter followers, which he began compiling on his "Silent Bob Speaks" website named after one of his more famous characters.

he end result is what Smith calls "part memoir, part advice to me."

"If you like me, I'm a good role model, and maybe you want to do the stuff I've done. But if you don't like me, you use that as fuel too, and you say, 'If this fat chump can do it, I should be even more successful,'" he said.

The book covers a wide range of topics from Smith's difficulties directing Bruce Willis in the buddy flick "Cop Out" to his veneration of hockey great Wayne Gretzky to drug use and his 2010 public feud withSouthwest Airlines.

Smith labeled the incident with the low-cost U.S. airline, in which he said he was ejected from a flight for being too big for his seat even though he could buckle his safety belt and put his arm rests down, one of the lowest points of his life.

After he was escorted off the plane, he unleashed a barrage of complaints about his treatment on Twitter and Southwest eventually apologized. But not before the press picked up on Smith's "too fat to fly" tweets.

"You had about 5,000 news articles on Google based on the tweet that I wrote, using my own words against me. That was hands down the low point," he said.

These days, he is keeping busy taking his comedy podcasts on the road for live shows and promoting the work of young independent filmmakers.

He also has an animated "Jay and Silent Bob" film in the works, and an unscripted TV show called "Comic Book Men" filmed inside of Smith's New Jersey-based comic shop. The TV program wrapped up its first season on the AMC network on Sunday.

"If you could figure out how to monetize passion, and that's pretty much what I do, then you've got your handle on something. Basically, I just kind of speak passionately about the stuff that I dig, and that creates content," he said.

(Reporting By John McCrank, editing by Christine Kearney and Bob Tourtellotte)