[Bish0pQ]

Some things you can do:
1) Learn from the hacking tutorials on sinister.li. There's a lot of content about hacking here, you should check it out.

2) Hacking challenges (websites that allow you to practise your web hacking skills legally) (list below)

Spoiler:

• HackThisSite
  
• Try2Hack
  
• Slavehack (not sure about this site though)
  
• HackThis (UK) (recommended)
  
• EnigmaGroup
  

3) You can setup your own vulnerable website to practise your skills (legally) on.
Here below you'll find some things that might come in handy (you'll have to install these yourself):

Spoiler:

• Damn Vulnerable Web Application (Well known, recommended)
  
• JuiceShop
  
• Hackademic
  
• Peruggia
  
• Bodgeit (weird name)
  

3) Try. Just try shit out, like everything. See what options things have. For example explore DOM or try to figure things out yourself. This might sound weird but you learn best when you find it out yourself.

4) Learn from YouTube. Below you'll find a list where you can start. I do not say this are the lists you need to know to become a hacker. You'll need to decide what you want to learn yourself.

Spoiler:

• SSTEC
  
• Kali Linux Tuts (that does not mean you can't run the scripts on another OS)
  

Hope I helped a bit.