If you have ever typed "how to draw" into YouTube, you have undoubtedly encountered the channel Proko. Run by Stan Prokopenko, Proko is widely considered the gold standard for art education online. But there is a massive difference between watching a Proko video and actually using the Proko Basic Drawing curriculum to get better.
If you are comparing it to other resources: Proko Basic Drawing BETTER
Center Lines: Always include the "spine" or center line to indicate which way the torso is twisting. Use the "3D Brick" Method Unlocking Your Artistic Potential: How to Use Proko
Perspective: This section teaches you how to create the illusion of depth using boxes, cylinders, and intuitive perspective tricks. and intuitive perspective tricks.