Someone posted here that they found it helpful viewing the chin area not as a big curved area but as a bunch of small flat planes. That really clicked for me. Trying to go round the chin in a curved stroke just ended with the blade embedded in the skin, with the scars to show for it. But taking short (half inch or less) strokes makes it go quicker and easier.
Another idea I've been toying with is trying to get as much of the chin and jawline as I can on the WTG downward pass, continuing from the cheek, over the jawline, to the neck. That works also going from the bottom of the lower lip area over the chin, carefully. If you can do that, and it does take a bit of trial and error and experience, then you won't have so much chin and jawline whiskers left to deal with. The chin and the corners of the mouth are the toughest for me.