A few widely recommended starting points are:

• Strobist: a strong online resource for learning practical flash and lighting basics. Its associated Flickr community is especially useful because people often share lighting diagrams, setup shots, and explanations of how images were lit.
• Light: Science and Magic: a respected book on lighting fundamentals. It explains core principles clearly and uses examples and diagrams to show how light behaves and how to shape it.
• Speedliting: another online resource focused on small-flash lighting techniques.
• Zarias white seamless tutorial: useful for practical studio-style lighting examples.

If you prefer visual, example-based learning, start with Strobist for hands-on setups and pair it with Light: Science and Magic for the underlying concepts. That combination gives you both the “how” and the “why,” which is ideal for building a solid foundation across portrait, still life, and other lighting-heavy genres.