Meta tags. Meta tags still play a vital role in SEO. If you type any keyword into a search engine, you’ll see how that keyword is reflected in the title for that page. Google looks at your page title as a signal of relevance for that keyword. The same holds true for the description of that page. (Don't worry about the keyword title tag -- Google has publicly said that it doesn't pay attention to that tag, since it has been abused by webmasters and all those trying to rank for certain keywords.)
The first relates to internal link structure. I’ve made the mistake you say you’ve seen so often. I have a primary keyword and have used that keyword in the main navigation, linked to a page optimized for that keyword. But I’ve also got a bunch of contextual links in posts pointing to that page, usually with the keyword in the anchor text. I now understand that those internal links aren’t helping much, at least from an SEO perspective. Am I better to remove that keyword and direct link from the menu and simply link the page from multiple posts and pages within the site. Or will I get better results leaving it in the main menu and changing the contextual links in the posts to point to a related page with a different keyword?
Many blogging software packages automatically nofollow user comments, but those that don't can most likely be manually edited to do this. This advice also goes for other areas of your site that may involve user-generated content, such as guest books, forums, shout-boards, referrer listings, etc. If you're willing to vouch for links added by third parties (for example, if a commenter is trusted on your site), then there's no need to use nofollow on links; however, linking to sites that Google considers spammy can affect the reputation of your own site. The Webmaster Help Center has more tips on avoiding comment spam40, for example by using CAPTCHAs and turning on comment moderation.
Do not be fooled by those traffic sellers promising thousands of hits an hour. What they really do is load up your URL in a program, along with a list of proxies. Then they run the program for a few hours. It looks like someone is on your site because your logs show visitors from thousands of different IPs. What happens in reality is your website is just pinged by the proxy, no one really sees your site. It is a waste of money.