Sid Vasandani from StyleMyPic has a really excellent channel on YouTube. He sells a panel for Photoshop that speeds up your retouching and makes some advanced editing techniques easier to do. His videos are to promote this, but he also teaches how to create the same effects without the panel. He is a great photographer anyway and his tutorials are very useful.
Sid deliberately uses very cheap photography gear like the Nikon D5100 camera, reflectors and Yongnuo flashes but using good photography technique and clever post-processing, he creates some really high-end results. His series of tutorials about how to make photos like Annie Leibovitz or Mario Testino are really incredible and it is worth watching, and practicing, all of them.