Where do I begin?
Basic Bug Bounty FAQ (dawgyg)
Book: Web Hacking 101 (Peter Yaworski)
Book: Real-World Bug Hunting: A Field Guide to Web Hacking (Peter Yaworski)
Mechanizing the Methodology (Daniel Miessler)
I heavily referenced this video when building my automated recon tooling with axiom. I split the logical tasks I did during large-scope recon sessions into their own files that accepted plaintext input and outputted the same. I chained them all together and ran the scripts on axiom with custom axiom-scan interact modules. I will be blogging more about this soon.