That article must be somewhat dated.
Points 1 is valid. Pagerank is mainly based on incoming links.
Point 2 is a bit dangerous at the moment because of Google penalizing sites for selling links.
Point 3 can be off the mark, most directories are worthless. Also consider this, Google is currently penalizing sites for selling links. Most directories have a paid submission service (ie you get listed faster if you pay), but not all directories differentiate between free and paid listings. What will Google do? Penalize all or none.
Point 4 building a sitemap is a very good idea. An XML sitemap will suffice for MSN Yahoo and Google. Yahoo does in fact use XML sitemaps. If you do not wish to sign up with each search engines tools then simply place the following line in a .htaccess file:-
Sitemap: http://domain_name/sitemap.xml
Or alternatively place the following in the head of your html page:-
<link rel="alternate" type="text/html" title="XML Sitemap" href="http://domain_name/sitemap.xml" />
and then ensure that http://domain_name/sitemap.xml is the location of your XML sitemap (for more information click
HERE. This site is a collaboration between the major search engines (including the 3 mentioned above).
Point 5 although you should try adding unique QUALITY content on a regular basis, if you do not have anything to post then quite simply don't post anything. If Google sees quality content being posted on a regular basis it is more likely to visit often.
Point 6 will help ensure that PR is spread about your site. The site with the highest pr tends to be your index page as it is where most people link too. By having a good linking structure helps spread the PR about so the index page's PR benefits the rest of the site.
Point 8 Google can tell if a link has been traded. Ultimately you want 1 way links to your site. If however there are sites that are of a similar content or of great importance to your visitors do link out to them and encourage them to link back. However if it is a 2 way link Google will not give it as much weight as if it were a 1 way link.
Ultimately you want to create content on your site that people will want to link too. Also try link baiting. If done correctly then you can reap a lot of incoming links from it. For example if you have thought of a tool that could be extremely useful, create it and let the world know. If it is truly useful other sites will link to the tool. Or as many advertisers do create a game or a funny video that people will want to link too.
Also do not be concerned too much with getting a high PR. A site can achieve a high PR but not achieve a decent rank. A PR in itself does not bring visitors to your site a decent rank combined with decent well laid out QUALITY content is what brings visitors in and keeps them.