Jama Jurabaev is a Senior concept artist at ILM. He’s gained a lot of popularity with his incredible 360 panoramic paintings that allow you to view not only a scene, but make you feel as if you are standing in a painted environment. In his tutorial, Jama goes through the process of how to create your own 360 painting, from the basics to some Photoshop tricks and shortcuts to finally by showing you how to upload it simply on ArtStation.
The grid provided below is what Jama uses as a guide to help him do his blocking in perspective.
The equirectangular image result: