Audit Area Section Check Item
Pages Default Page 1- Use default page instead of redirection
2- Use friendly name
Main page Seo and the Main page
Optimize the main page of your site (domain name, index.html) for word combinations that are most important. This page is most likely to get to the top of search engine lists. My seo observations suggest that the main page may account for up to 30-40% percent of the total search traffic for some sites 
Dyncamic and Static Pages For dynamic pages, SEO crawelers cannot drill on, so you should do the following:
1- create also static pages and put the link of dynamic pages in to let search index your page
2- Eliminate Special characters like ? & in your URL, so you should rewrite URL, for example:
Old : /?Cat=Shoes/Color=red&size=8
New for SEO : /Shoes/red/8
3- Create dynamic page title according to the previous content we displayed in search result according to the user friendly URL
Ex: Red Shoes, Size 8 ,from your web site
4-Create a custom 404 page: If the webpage is not found in the searches, then the redirect will take the search engines to this custom error page. The URL will be checked in the custom error page and based on that URL, it will be redirected to the corresponding dynamic page, thereby achieving the targeted search engine rankings.
5- Create dynamic Sitemap for your most commonly used URL, that engine can visit it because it does not appear in the UI, but it can still visit it
6-Exclude non content related parameters from the URL
7- Use short URL's instead of long, because it's easy for Search engine
Performance If your web website is slow in browsing pages, google will demote your ranks, because search engine targets to help his users in with good search result
CSS don't use inline CSS, use external stylesheets whenever possible
JS don't use inline JavaScript, use external .js files instead
HTML Comments don't leave HTML-comments
Default Page don't use viewstate when not necessary
Default Page don't use a <form runat="server> when not necessary (comes with hidden fields)
Menus don't use Flash/Silverlight to show information or for menus
Number of pges The general seo rule is: the more, the better, more pages, more ranking. Increasing the number of pages on your website increases the visibility of the site to search engines. Also, if new information is being constantly added to the site, search engines consider this as development and expansion of the site. This may give additional advantages in ranking. You should periodically publish more information on your site – news, press releases, articles, useful tips, etc. 
Menus don't use JavaScript-based menus
Menus don't use button-based menus
Site Map do use a sitemap (CP-article: Simple Sitemaps in ASP.NET)
AJAX and Search Engine Optimization
Ajax uses JavaScript and search engines don't like JavaScript. So, your Ajax site have big potential problem. It is very possible that your content will not be indexed. You can disable JavaScript in your browser and try to access all content on site. If you can't see it without JavaScript, spiders will not see it too.
Possible solutions are to provide site map with links to all content, or add additional way of navigation that uses static links, or to make your content initially loaded without JavaScript.
HTML Headers Use <strong>, <h1>, <h2>, <h3>,
Use the HTML markups <strong>, <h1>...<h6> regulary - use them to structure the site's content. These markups are made for weighing some words more than others - so it is for search engines. Use these markups whenever it's useful to do so.

References HREF & Links do use simple <a href> tags whenever possible
HREF & Links do use the "title" property for <a href>
   
HREF & Links Link to others
links to your site have the biggest influence to your sites' ranking. Try to get linked from as many other websites as possible. Use social bookmarking and other social services like digg.com to get more links and more visitors.
Be connected to others Always keep pages conntected to at least one page of the site
Different Language Do not make links to different language.
Social Media Accounts Add social media links to your web site, it makes u ranked up
Broken Links Eleminte broken link.
HREF & Links don't use massive line-breaking (twenty lines with only a linebreak or something similar)
RSS do use RSS (syndicate all your content, when possible)
MetaTags Meta Description 1-Page title should be consistent with the main web site, and related or Inherit from your main site name
2- Meta description is related to your page title
3-   This is used to specify page descriptions that will be shown by the search engine when you appear in the search result, so it will encourage the user to enter your website.
It does not influence the seo ranking process but it is very important. it guarantees large numbers of visitors. 
Size of text title<=65 char
Description<=165 char
Keywords<=100 word, Recommended 5-10
Keywords Numbers Keywords must be used at least three to four times in the page text.
Keyword phrases (word combinations consisting of several keywords) are worth a separate mention.
The best seo results are observed when a keyword phrase is used several times in the text with all keywords in the phrase arranged in exactly the same order.
In addition, all of the words from the phrase should be used separately several times in the remaining text. There should also be some difference (dispersion) in the number of entries for each of these repeated words. 
Keywords denisty  Keyword density and seo
   Keyword page density is a measure of the relative frequency of the word in the text expressed as a percentage. For example, if a specific word is used 5 times on a page containing 100 words, the keyword density is 5%. If the density of a keyword is too low, the search engine will not pay much attention to it. If the density is too high, the search engine may activate its spam filter. If this happens, the page will be penalized and its position in search listings will be deliberately lowered.
Keywords location The closer a keyword or keyword phrase is to the beginning of a document, the more significant it becomes for the search engine. 
Description and keywords Page.MetaDescription = "This is my great page";
Page.MetaKeywords = "great,page";
Page MetaTags Create unique short descriptive title for every page.
Page Title Every page of web site needs to have its own unique title.
Title Characteristics Title should be short, descriptive, meaningful, contains keywords and relevant to content of the page. 
Repeated Phrases Do not insert repeated phrase like company name on the beginning of the title of every page.
Sometimes you can choose two or three related phrases, but you should certainly not try to optimize a page for 5-10 phrases at once.
Information Location Let your most relevant information appears first. 
meta data Such phrases would probably produce no effect on page rank. 
Content Duplication Avoid duplicate content, so use redirection of sites instead of duplication
Black and white SEO do not use black methods in keywords
Power Words Use power words like:
Today,Now,WOW,New,Free…
Be crawable do use pings for search engines (use http://pingomatic.com/)
Image Text do use the "alt" property for images, it represent  the alternative text for the image
ViewState Reduce the usage of view state because the search engine reads only the first 100K, and use the following direction:
If you really need a ViewState there is new option in web.config to place it to the bottom of the page:

<pages renderAllHiddenFieldsAtTopOfForm="false" />
Images «ALT» attributes in images
   Any page image has a special optional attribute known as "alternative text.” It is specified using the HTML «ALT» tag. This text will be displayed if the browser fails to download the image or if the browser image display is disabled. Search engines save the value of image ALT attributes when they parse (index) pages, but do not use it to rank search results.
Currently, the Google search engine takes into account text in the ALT attributes of those images that are links to other pages. The ALT attributes of other images are ignored. There is no information regarding other search engines, but we can assume that the situation is similar. We consider that keywords can and should be used in ALT attributes, but this practice is not vital for seo purposes.
Main Features Deployment model Incerease enhancement to let Search engine finalize better.
Security Secure your solution, because google block infected sites, and then bad rates
Deployment model Eleminate shutdowns.
ROBOTS file should be used to tell SE,how to deal with your site. While there are legitimate reasons for excluding pages from robots.txt, do it sparingly: excessive blocking could be the cause of your penalty.