To make mulled wine at home, add orange slices, cinnamon, cloves, star anise, a liquor of your choice, 2 teaspoons of your preferred sweetener, and wine in a saucepan and stir it properly until it mixes well.

Once you are done stirring, start cooking the wine on medium to high heat until it sort of reaches a simmer. Ensure the mixture doesn't bubble as you do not want the alcohol to evaporate. Once it almost reaches the point of simmer, lower the heat and let it cook this way for anywhere between 15 minutes to 3 hours. This is entirely dependent on how strong you want the flavor to be. 

Thereafter, use a strainer to remove and discard the orange slices and the spices from the drink. At this point, taste the drink a little and feel free to add more of the sweetener if you need to. 

Add some spices and orange slices as garnish. Voila! your warm 'Christmasy' drink is ready! Serve it warm or else store it in an airtight container in the refrigerator.