The Ever Expanding Page of Writerly Resources
http://www.publishingcrawl.com/ everything about every part of writing, and publishing can be found on pubcrawl.
http://susandennard.com/for-writers/ one of the most comprehensive list of articles by Susan Dennard covering writing and publishing.
https://dailydahlia.wordpress.com/site-guide/ Everything from querying to post publication, and a whole slew of stuff I've not read anywhere else!
IDEAS AND COMMERCIABILITY
PLOTTING & STORY STRUCTURE
HISTORICAL WRITERS RESOURCES
WRITING DIVERSE CHARACTERS
QUERIES & QUERYING
http://tracichee.com/post/113342540667/query-tips-2-research-resources : giant resource page by Traci Chee
https://www.youtube.com/watch?v=w5UELO1LwiM : great video on agents in general with advice on comp titles at the end.