If you have many links on your website and no back-links (the other website don´t link back) you will be downgraded by the search-engines. If you set your outgoing links as rel="nofollow" - you will not be downgraded by the search-engines.
Building a landing page may be better then focusing on the frontpage. The landning page should be using the site keywords and having a unique material. When other sites link to you - they link to your landing page (and not your frontpage)
Try to keep your visitors for a long time - you need to have a good average time. Incourage your visitors to stay by finding ways to keep them interested; suggest other articles, have polls, have lots of information.
A sitemap is a structured way to "map" your internal hierarchy. Headlines and sub-headlines can be used in the sitemap leting the crawlers getting an overview of the content. You can upload your sitemap using Googles Webmaster tools.
Meta description or site description is a text that should describe your website. Use meta tags/keywords an repeat them in the description. The description is shown in the search result when people use the search engines.
Meta tags was the big thing couple a years ago. The search engines took a big part going for the meta tags. A meta tag is simply keywords for your site. For example "cars", "Sweden", "Toyota" etc. The meta tags doesn´t have the same influent regarding search engines these days. Still, it´s usefull for the website owner structure the profile of the site. Meaning, keywords/meta tags can be useful when making a website profile.
A link directory is similar to a library but instead of books, link directories categorize links. The difference between a link directory and a link farm is that the first on has a description and categories for each link. You should not use link farms. Please submit your link to our link directory for free.
Search engines really likes when other websites link to your site. You got a really good rating when websites ranked better tehn yours link to your site. Get all websites that you can link to your site. Especailly sites that are in the same "area" like your site.
Search Engine-Friendly URLs or simply SEF URLs are readable URLs. For an example http://www.mywebsite.com/seo/Search-Engine-Friendly-URLs.html is a readable URL, http://www.mywebsite.com/item39.php is not. Keep your URLs SEF both for search engines and people.
Use headings, H1 and H2 tags - keep a site hierarchy and let headlines and keywords be in the H1 and H2 tags. Headline should go in H1 and sub-headline in H2. If you are using a CMS see to that the template are using H1 and H2 tags.