Every time someone creates a website for the first time, they have wild dreams that millions of people are going to see their site and that they will make a ton of money or raise awareness to a cause they believe in. Sadly this is not the case. There are allot of factors that go into building a website that determine whether or not your site falls into the "invisible web" or is seen by millions of people.
This is where SEO comes into play. Search Engine Optimization consists of many different techniques and combined increases your web sites visibility when someone uses a search engine like Google or Yahoo!. Fact is most people when searching for a specific subject, normally do not go past the 2ND or 3d page of search results. So how do we get up in rankings of a search engine? First off you do research. You check out the main sites you see on a specific subject and find out what they are doing to have such a high ranking. You will notice the placement of keywords, robots they use, there description in there title tag, how relevant the keywords they use pertain to the content of their web site.
Those concepts of placement of text and the order the search engine crawls your site, with robot txt giving importance to specific content it wants the search engine to crawl. I used all the possible techniques you listed, but my site still has a low ranking you say. Well allot of search engines for a fee will boost the ranking of your site. Also it is up to you to let the search engine know your site exists. Also the more number of hits to your site increases your search engine ranking.
USE VIRAL MARKETING! Just because we live in a world where actual human contact is no longer needed to live @.@ does not mean that word of mouth is dead. Use the people you know to your advantage. Have them help you generate a buzz about your site. Family members, close friends and co-workers are great tools to help get your name out there. Also have interesting content and encourage users to pass the virus of your website to others, for example, YouTube does a great job of this by adding a share button with every video posted on there site. This allows the user to send the video to others with YouTube name on it. Then that person can send it to others and so on.
There are helpful free tools out there from Google and Yahoo! that will assist you on optimizing your site. I strongly recommend you use these tools. It is not easy when creating a site for the first time, but use your social networking tools, friends and family, and keep track of your placement and content you use, plus with some good old fashion research, you will not be left wondering why your site never took off.