In order to pass this test you must create a sitemap.xml file for your website. Some of the best practices are listed below:

• It is strongly recommended that you place your sitemap at the root directory of your website: http://yourwebsite.com/sitemap.xml But in some situations, you may want to produce different sitemaps for different paths on your site (e.g., security permission issues)
• Sitemaps should be no larger than 10MB (10,485,760 bytes) and can contain a maximum of 50,000 URLs. This means that if your site contains more than 50,000 URLs or your sitemap is bigger than 10MB, you must create multiple sitemap files and use a Sitemap index file
• All URLs listed in the sitemap must reside on the same host as the sitemap. For instance, if the sitemap is located at http://www.yourwebsite.com/sitemap.xml, it can't include URLs from http://subdomain.yourwebsite.com
• Once you have created your sitemap, let search engines know about it by submitting directly to them, pinging them, or adding the sitemap location to your robots.txt file
• Sitemaps can be compressed using gzip, reducing bandwidth consumption

sitemap.xml example:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
<url>
 <loc>http://www.yourwebsite.com</loc>
 <lastmod>2013-01-01</lastmod>
 <changefreq>weekly</changefreq>
 <priority>0.9</priority>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/100</loc>
 <changefreq>weekly</changefreq>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/101</loc>
 <lastmod>2013-01-02</lastmod>
 <changefreq>weekly</changefreq>
</url>
<url>
 <loc>http://www.yourwebsite.com/articles/102</loc>
 <lastmod>2013-01-02T13:00:12+00:00</lastmod>
 <priority>0.5</priority>
</url>
</urlset>

In order to pass this test you must add an alt attribute to every <img> tag used into your webpage.
An image with an alternate text specified is inserted using the following HTML line:

<img src="image.png" alt="text_to_describe_your_image">

Remember that the point of alt text is to provide the same functional information that a visual user would see. Search engines, users who disabled images in their browsers and other agents who are unable to see the images on your webpage can read the alt attributes assigned to the image since they cannot view it.

Learn more about optimizing images for SEO.

Your two options for file compression are Deflate and GZIP.

• Deflate is an option which comes automatically with the Apache server and which is simple to set up.
• GZIP on the other hand needs to be installed and requires a bit more work to install. However, GZIP does achieve a higher compression rate and therefore might be a better choice if your website uses pages which have a lot of images or large file sizes.

Setting up file compression for your website will depend on which type of server you?re using for your website. Most likely, you?ll be using Apache, which means you can enable compression by adding a few deflate codes to your .htaccess file.

# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

For more advanced information regarding deflate you can check this Apache documentation.

In order to reduce the number of HTTP requests, you can use the HTTP Expires header to set an expiration time for your images or any other content type. You can add the following lines into your .htaccess file:

<IfModule mod_expires.c>
    ExpiresActive on
 
    ExpiresByType image/jpg "access plus 1 month"
    ExpiresByType image/jpeg "access plus 1 month"
    ExpiresByType image/gif "access plus 1 month"
    ExpiresByType image/png "access plus 1 month"
</IfModule>

In order to pass this test you must consider using a 301 re-write rule in your .htaccess file so that both addresses (http://example.com and http://www.example.com) resolve to the same URL.
- If you want to redirect http://www.example.com to http://example.com, you can use this:

RewriteCond %{HTTP_HOST} ^www\.example\.com$
RewriteRule ^/?$ "http\:\/\/example\.com\/" [R=301,L]

- If you want to redirect http://example.com to http://www.example.com, you can use this:

RewriteCond %{HTTP_HOST} !^www.example.com$ [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301]

Note that you must put the above lines somewhere after RewriteEngine On line.

In order to pass this test you must make your email addresses invisible to email spiders. Note that the best option is to replace your entire contact mechanism with a contact form and using the POST method while submitting the form. Other solutions are listed below:

• replace the at (@) and dot (.) characters
• replace text with images
• use email obfuscators
• hide email addresses using JavaScript or CSS trick

If you want search engines to crawl all the outgoing links on your webpage you must remove the nofollow meta tag.