Complete Guide on SEO for Drupal

1. Enable Search Friendly Urls - The very first thing you want to is to enable search engine friendly urls. You should see this option at the time of installing Drupal but in case you missed it, you can go to Modules (/admin/build/modules) and enable Path module which comes with core installation but is disabled by default. Path module will convert /node?q=1 urls to /node/1. 

2. Install Pathauto Module - Install pathauto module too which allows you to create search engine friendly urls. PathAuto module offers various settings like removing characters like a,an,the as well as to write your own custom paths using tokens. 

3. Install Global Redirect Module - There is a Global Redirect module which is a must as it will take care of the canonical url problems as well as it do 301 redirect from urls like /node/1 to /node/my-name so if you access /node/1 or /node/1/ it will redirect to /node/my-name 

4. fix Robots.txt - Drupal comes with default robots.txt which hides most of the system files and directories but still if you are looking to block some pages from search engines, you want to edit the file and add the paths. There is a module robots.txt but I feels you are better of editing it manually. Do note that you need to remove/rename the default robots.txt file if you are using the module. 

5. Redirect www to non www or non www to www in Drupal - If you are not redirecting one to other, search engines will treat www and non www as two sites which can cause lot of unnecessary duplication and the server will get hit twice by bots. Also on social media, some of your links will be www and some will be non www, again something which you can avoid. At inBoundio, I redirect non www to www so you can do something similar. If you look drupal code hosted at github, https://github.com/drupal/drupal/blob/7.x/.htaccess is the .htaccess file which is well commented for you to make changes. You can also do it at php lever adding some 301 redirects but since .htaccess is read by web server first, the client http request never hits your drupal installation reducing the memory usage.

  # To redirect all users to access the site WITH the ‘www.’ prefix,
  # (http://example.com/… will be redirected to http://www.example.com/…)
  # uncomment the following:
  # RewriteCond %{HTTP_HOST} .
  # RewriteCond %{HTTP_HOST} !^www\. [NC]
  # RewriteRule ^ http%{ENV:protossl}://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

  # To redirect all users to access the site WITHOUT the ‘www.’ prefix,
  # (http://www.example.com/… will be redirected to http://example.com/…)
  # uncomment the following:
  # RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
  # RewriteRule ^ http%{ENV:protossl}://%1%{REQUEST_URI} [L,R=301]

7. Path Redirect Module - If you are changing url of an older page say /older-page to /newer-page, you don't want older page to give 404 page not found error but still want it to 301 redirect to the new page. This can be done with Path_Redirect module. There is also path access module too which can be used to block some urls from search engines (in drupal that will anonymous role type)

        

11. XMLSIteMap and Sitemap module - if you are running a big site with many internal urls including those which are not linked from other pages, you can use xmlsitemap module which creates a sitemap of all the urls (depending on the settings) and also submit it to the search engines. There is also one more sitemap module which creates link sitemap unlike xmlsitemap, which can be handy as an index page for the site.