a) External Links.It is probably one of the most important factors in having a highly ranked website in search engines. Links from other websites pointing to yours is your best bet in having a top index ranking. Unfortunately, it is also the most tedious and time-consuming to do. Normally, this is achieved by offering reciprocal links with other websites. To do this you must contact them and see if they are willing to do this. It is also important to note that websites that are not highly ranked in search engines do not contribute much to your search engine ranking when they link to you. Try to get links from highly ranked sites.
b) Internal Links.It is important for individual pages of your website to have access to the rest of the site. This allows search engines to crawl the rest of your site once they have indexed one of your pages.
c) Anchor Text. The words used to link to your pages, that is, the text between the <href> and <a> tags, add weight to your search engine placement. Whether the link come from outside or within your website, it is best to make the anchor text incorporate some of your keywords.
e) Dynamic pages. Non-html pages like asp, aspx, php, cfm are generally not indexed by a lot of search engines. Do not place important content on such pages. It is also important to note that some sites that provide reciprocal links use dynamically generated back-links which are not indexed by search engines, thereby nullifying the advantage of having an external link. Make sure that links pointing to your site are in plain HTML.