General Resources

There are loads of sites to learn from if you're an absolute beginner:

Useful Websites

W3Schools A good reference guide for loads of languages, including HTML, CSS, JavaScript, SQL, Python, PHP, Java and more
Codebar Loads of tutorials for HTML, CSS, JavaScript, Ruby and Python, plus introductions to the Command Line and Git
freeCodeCamp Tutorials for HTML, CSS, JavaScript, and Python, along with loads of certifications