Search engine optimization is about (1) some basic technical steps that most standards-complaint developers understand, and (2) making your website worth caring about so people WANT to link to it. At least, that's the non-sleazy kind of search engine optimization.
The magic spell you're referring to is just that; a magic spell. The reality is that these people make hundreds, if not thousands of these "niche sites", and 1 in 100 is marginally successfully. They do it at such volume and with such an efficient system of rolling out template websites with useless filth the internet doesn't need that they can turn a profit.
But their real profit comes from selling their system, using select stories like the ones you've heard, or generating a month or two of profits and then flipping the website to another owner. Unfortunately, these websites rarely maintain said profit.
The real question you have to ask is whether you would rather make an average of $5 per month off of 200 websites, or $1000 per month off of 1 website.
For a technical person, there's no doubt that the 1 website is the "easier" road, and it ain't easy. But 200 websites making $5/month ain't easy either. The people doing so have an extensive and intricate understanding of internet marketing sleazeball tricks, the same way many technically-oriented hackers here know their craft inside and out (the good and the bad).
Still, there ARE some quick things you can do to optimize your pages and create your own “link neighborhood” when you launch a fresh site. Real success comes from really making something HUMAN BEINGS want to visit... but these things will jump-start you once you have that material.
1. Pick a domain name that matches your primary keyword.
2. Get other important keywords into the secondary page URLs using mod rewrite (or a platform that supports it, like Wordpress).
3. Make sure every page has a unique title and H1 tag that matches your primary keyword objectives for that page.
4. Make sure the homepage links to most, if not all, other pages (at least to start).
5. Make sure every page links back to the homepage and many other secondary pages using appropriate anchor text.
6. Register on every social media site that makes sense for you (using this list). Include a link to the site in your profile. It helps if the username you choose is a primary keyword.
7. Link the social media profiles to each other where applicable. Fill them out as fully as possible.
8. Actually use the social networks. More activity will create more pages of content with more links to the profiles, in turn passing more “juice” to your website.
9. Claim your site using Google Webmaster Tools. Submit your sitemap (preferably one that is automatically updated).
10. Do a Google Search for every one of your top keywords. Figure out how to get a link from any site showing in the top 20 results.
11. Do not under any circumstance pay someone for a link. Do not offer or accept offers to trade links.
12. Avoid linking out to shady websites of any kind.
13. Study the keywords your competitors target (if they use meta-keywords like bozos, you can just lift those from the source).
14. Write a blog, or find some other way to continually add new content. This adds to the content you have indexed, but is also another opportunity for links. Long term strategy right here.
15. Build a Twitter client, wordpress theme, or something else that people will link to and use with persistent links to whatever you decide is in the by line.
Follow these tips and you’ll end up with a few hundred links to your site. That should get you indexed and off to a start, but its no replacement for the real work of being worth caring about.