If you are managing your own website and SEO there are a number of tasks that you should be doing on a monthly basis.
One of the tasks that I would recommend is submitting your xml sitemap to Google and Bing. This will help search engines index any new pages that have been generated on your website.
The steps below go through the process of generating your xml sitemap in WordPress and submitting the sitemap in Google Webmaster Tools. You can generate an xml sitemap using most content management systems quite easily. I chose WordPress as an example as it is the most commonly used content management system. I would also recommend submitting your sitemap on a monthly basis to Bing. You can do that here
Steps for Generating and Submitting a Sitemap
Step 1. Login to your website.
Step 2. Click on Settings > XML Sitemap.
Step 3. Click Re-build the sitemap manually.
Step 4. Login to Webmaster Tools. Go to https://www.google.com/webmasters/tools
Step 5. Click on Sitemaps.
Step 6. Tick the box beside the sitemap and click re-submit.