Hey, thx for joining us!! Since you’re just starting, I would recommend doing a little research on some of these topics: XSS, SQL injection, Phishing, Cryptography, packet sniffing, man-in-the-middle attacks, hash cracking, XSRF, network hacking, DoS attacks, malware, JavaScript, OS vulnerabilities, and command injection. This is not meant to be overwhelming, and you don’t have to be a master at all of these things to be a good hacker. In my opinion, since you’re just starting off as a hacker, these are the only ones you REALLY need to understand: XSS, SQL injection, malware, phishing, cryptography, and Javascript. Happy hacking!!
P.S. As WHGhost said, doing the levels is a great way to learn.