In my years as a ServiceNow Administrator, Developer, and Implementer there have been a few blogs that have repeatedly been a great source of information. The list below contains the blogs that I most frequently have found useful:
  1. http://www.servicenowguru.com – (Mark Stanger – my Mentor at Crossfuze Solutions) – My favorite technical resource of ALL things ServiceNow, if you’ve been struggling or had a problem with it, there is probably a post about how to fix it here!
  2. http://www.john-james-andersen.com/category/blog/service-now – (John James Anderson) – good blog on Integrations (REST, etc.)
  3. http://snaug.com – (Sal Costa) – Good source of Jelly, CMS related info
  4. http://www.servicenowelite.com/blog – (Mike Kaufman) – Good source of everyday usage tips
  5. http://www.snc-blog.com – (Logicalis SMC) – Good source of everyday usage tips
  6. http://serviceportal.io – (Nathan Firth) – Good source of ServicePortal, CMS, Angular tips
  7. http://www.cavucode.com/blog?tag=GenevaGems – (John Roberts) – Good info on Geneva (GenevaGems) and Fuji (FujiForty) enhancements
  8. https://sncommander.com – (Joel Maxwell) – Good general source of ServiceNow tips
  9. http://www.goranlundqvist.com -(Goran Lundqvist) – Good solutions to  specific use cases (now posts on SN blog too)
  10. http://servicenowtips.tumblr.com – Good ServiceNow nuggets, but hasn’t been updated in a while.
  11. https://community.servicenow.com – (ServiceNow) – Good Q&A on various issues
  12. https://community.servicenow.com/community/blogs/blog – (ServiceNow) Good posts about ideas/solutions for various issues
  13. https://hi.service-now.com/kb_view.do?sysparm_article=KB0552847 – (ServiceNow) Good CMS Resources – (Thank you to Robert Chrystie)
Good ServiceNow Related Books:

Mastering ServiceNow Administration –  (Martin Wood) – Good book for Administrators at all levels. Takes the reader through creating a Hotel App which is a great way to cover all the various usages of the covered functionality.

Mastering ServiceNow Administration Second Edition – (Martin Wood) – Follow up to first version (above). Due out in October.

The Principles of Object-Oriented JavaScript – (Nicholas C. Zakas) – Great book for learning about how Objects work in JavaScript. From a ServiceNow perspective, think about how to apply these principles in your Script Includes.
As I’m sure there are some I’m missing, please respond in the comments to other great ServiceNow blogs/books you have found useful.