Check out the fine skin fade skills of barber Sam Hill out of the Cut & Grind shop in London, UK. The "customer" in the chair getting his hair cut is actually fellow barber and shares his first name - Sam Galvin.
Sam starts off the fade on the side of the head and creates the line towards the back of the head. He will focus only on one side at a time and work on blending the fade perfectly. In this video he is doing a mid fade and leaving the top of the hair and the beard untouched.
In progressive fashion, Sam will start from the sideburns area and use an electric razor to bring the length to a zero. He'll follow his line and towards the back of the head and lower neck. After that, he pulls out the clippers and begins the fade by starting off without a guard, adjusting the clippers a little deeper, and then eventually adding guards as he goes up the head.
Once he's mastered the side of the head, he'll knock out the other side and bring it together on the back of the head. One tip that helps with the blending of the fade is to use scissors in an upward fashion to add any lightening that is needed. He picked this up from YouTuber AndrewDoesHair.