First of all, realize that what anyone says about Google and SEO is an opinion... Google keeps its algorithms for ranking pages to itself, and changes them without notice, so whatever people "know" about Google is inferred from analyses of actual results. That's why you'll see differences of opinions out there. The following is based on what I've learned over the past couple of years... and I've gotten my main site to rank in the top 10 on the Google searches that matter to me. So mileage may vary. I do know that getting a good ranking takes work and time, there's no quick, magic fix no matter what "experts" say.
Here's a
short article that describes metatags. Keywords used to be important, most SEO articles I've read recently say they're not as important to search engines as they once were. Most everyone agrees, though that the Description metatag *is* important. Note from the example on the linked page that they go into the HEAD section of your page. How you would do this depends on what you're using to build your web pages: template based web site tools often have an option somewhere to set metatags.
There are H1 to H6 headers you can place in your pages. They're kind of like the header styles provided in a word processor like Microsoft Word. Some template-based web design tools have a place to specify a page header; this is usually the H1 header. Others provide a way to set the style for a line of text to H1 - H6. Again, it depends on what tool you're using.
Here's a page that describes the headers and gives the code for them.
A "link farm" is a site that just provides a big list with a lot of links - it's thought Google and other search engines will penalize your site if they think it's listed on a "link farm". You might find yourself listed on link farms without your requesting to do so; not much you can do about that, but you shouldn't voluntarily request a link on a farm. Note that site directories like Yahoo, Google, DMOZ are not link farms and it's good to be listed on directories.
Links from sites like Squidoo, MyBlogLog, Facebook are helpful because these are "quality sites" in Google's eyes... they have high rankings themselves. Links from your brother-in-law's wedding site are not helpful, because it doesn't qualify as a "quality site".
A sitemap is very important... you've seen these on other sites (if not, look around at big commercial sites - they'll all have sitemaps, usually with a link at the bottom of the page). Google uses them to rank your site. To create a sitemap, you need a page with a list of your site's URLs, plus an XML site file that you upload. You also should tell Google that your site has a sitemap. Here's the
Wikipedia entry on sitemaps; there are useful links at the bottom.