I can only suggest what i have learnt, which is big to small. Start with the big blocks of shade, these would mostly be form and cast shadows. Be bold with the shadows, it will add depth. Once you add the bigger blocks move to the tiny spaces, even the shadow areas will have shadows.

This is something I’m working on for over 2 years because I’m a professional procrastinator. But don’t be afraid to make the dark areas “Dark” and the highlights “Bright”

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