Creating a clock in Sketch might not sound exciting at first, but we’ll discover how easy it is to recreate real-world objects in a very accurate way. You’ll learn how to apply multiple layers of borders and shadows, you’ll take a deeper look at gradients and you will see how objects can be rotated and duplicated in special ways. To help you along the way you can also download the Sketch editable file.
This is a rather advanced tutorial, so if you are not that savvy with Sketch yet and need some help, I would recommend to first read “Design a Responsive Music Player in Sketch” (Part One | Part Two) that cover a few key aspects in detail when working with Sketch. You can also have a look at my personal project sketchtips.info where I regularly provide tips and tricks about Sketch.
Source: Smashing Magazine How To Create A Realistic Clock In Sketch