Some programming considerations to improve SEO.

To improve SEO, I will suggest that you use a CMS or framework rather than a custom approach when developing a website. The reason for this is that a lot of considerations regarding SEO have already been taken into account while programming a CMS. Among these CMS, those that are performing well on search engines are WordPress, Joomla, Drupal, etc.

Now coming to the point that which 5 things are most important from a programming point of view are,

        Site loading speed.
        Onpage CSS and Javascript
        Etags
        Concept of Cache
        A properly configured .htaccess file
        Coding according to W3C recommendations
        Programming URLs and meta tags dynamic 
        Proper Site Map

Site Loading Speed:

The first and major factor for onsite optimization on the programming side is increasing site loading speed. There are a huge number of things that could be considered for decreasing the loading time of a site, but I will discuss the most important here.

Select the best hosting services.Estimate the amount of traffic your site could get and buy web hosting based on it. Keep in mind the bandwidth they are offering.

Some key elements to improve site loading speed are: using gzip compression, avoiding parallel queries, Improve your site code, Using CSS Sprites, Minify CSS, and JS, Using page speed testing tools

On page CSS and Javascript.

Use as little on-page CSS and Javascript as possible. The same thing implies inline CSS and Javascript. The major mistake they make is definitely increasing the page weight. The more CSS and Javascript on your page, the more difficult it is for the search engine crawler to crawl your page. When the crawler is not happy, your page will lose importance in its eyes. This type of code is also difficult to modify. If you must have to declare JS on the page, always write the code at the bottom of the page.

Configuring ETags

Etags are normally used to decrease the payload size. This means that entity tags (ETags) are a mechanism that web servers and browsers use to determine whether the component in the browser’s cache matches the one on the origin server.

Concept of Cache:

Web caching is used to reduce web traffic and thus bandwidth consumption.The cache normally saves copies of HTML files and images and exists between the server and the client requesting the web page. Cache could be implemented using PHP, but the best way is to use the.htaccess file.The only requirement for the.htaccess method is that mod_expire be installed on your web server.

You can get most detailed tutorial on cache concept on http://www.mnot.net/cache_docs

A properly configured .htaccess file

With the help of the htaccess file, the default configuration of the Apache web server could be overwritten, plus it can do a lot more than this. This file is normally placed in the web root and affects all the subfolders. But when you place it in a subfolder and the main root folder also has an htaccess file, then the main htaccess file will be overwritten for that specific subfolder.

Now, when this file is properly configured, it definitely has a good impact on improving SEO. You can make your urls SEO friendly by configuring ETags, applying cache, using url redirect, creating pages for 404 and 500 errors, redirecting the url to these pages, and many other SEO benefits.This file could be edited easily using a normal notepad. The following is the best and most in-depth tutorial on the.htaccess file.
http://httpd.apache.org/docs/2.2/howto/htaccess.html

Coding according to W3C recommendations

If you’re a web developer, you’ve probably heard of W3C.It stands for the World Wide Web Consortium. When you code according to the recommendations of the W3C, chances are that this will also have an impact on improving SEO, as it increases accessibility and has a direct or indirect impact on decreasing bounce rate.

For more information on coding standards, please visit http://www.w3.org.

Creating SEO-friendly URLs and making meta tags dynamic

Always programme dynamic urls and meta tags / titles when doing front-end development.i.e., they should change according to the pages of the site. Search engines place a high value on pages that include keywords in the URL.URLs with the query string “?” are highly discouraged by the search engines. So, always use aliases in the urls rather than ids. The same thing applies to meta tags, like keywords and descriptions. They should also be dynamic and need to be changed page by page.

Proper Site Map

A proper sitemap is also required for proper indexing of all site pages. It is an XML file that is put in the main root directory of the site, telling search engines about all the pages that particular site has that could not be discovered otherwise by the search engines. It also gives additional information regarding the content of the site and thus increases visibility.