Article: Make sure that the mixture is evenly spread out over the base of the shallow dish.   The mixture will set as it dries and adhere to the glass.

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Fill a shallow dish with about half an inch/1 centimeter (0.4 in) of water. Fill another shallow dish with the sugar and cinnamon. Mix the sugar and cinnamon together with your fingers. Dip just the rim of your martini glass into a shallow dish of water. Now dip the wet rim into the sugar and cinnamon mixture. Set the glass aside.