The following resources will help you get started or improve your skills in web hacking / bug bounty.
Great resources to get you started
If you're new to web security, it can be difficult to know where to begin. That is why PortSwigger created a suggested learning path to point you in the right direction. Learning Path - Web Security Academy
The Intigriti Hackademy is a collection of free online learning resources in the field of web security. For every vulnerability category, you will find a detailed explanation with real-life examples, write-ups, bug bounty tips, ...
Bug Bytes is a weekly newsletter curated by members of the bug bounty community. The first series is curated by Mariem, better known as PentesterLand. Every week, she keeps us up to date with a comprehensive list of write-ups, tools, tutorials and resources.
PentesterLab - We make learning web hacking easier! Our exercises cover everything from basic bugs to advanced vulnerabilities. Not only will we help you learn but you'll also have fun doing it!
List of bug bounty tips
Videos / channels
intigriti Hackademy videos by PwnFunction
You've got pwned: exploiting e-mail systems by @securinti
Web Hacking 101: Hacking Pro Tips by Peter Yaworski
Real-World Bug Hunting: A Field Guide to Web hacking by Peter Yaworski
The Web Application Hacker's Handbook 2nd edition by Dafydd Stuttard & Marcus Pinto
Web Hacking 101 by Peter Yaworski