Start by launching your image editor. Create a portrait-oriented document sized 11 inches by 17 inches with a resolution of 300. This is a standard size for posters. However, if you need a smaller poster, you can choose 8.5 inches by 11 inches. If you need larger size, you can go with 18 inches by 24 inches.
I want a simple background for my poster, so I selected a nice and clean blueprint paper texture. I downloaded and opened it in the image editor, and then I imported it into the newly created document. I also resized it to match the poster measurements.
Graphics need to be distinctive and colorful enough to draw the viewer’s attention. Find something that will immediately speak of Christmas to put people in the right mood. Choosing traditional imagery, even with an original twist, is the easiest way to achieve this. For this sample poster, I picked a cartoony Santa hat. Its basic red and white colors contrast nicely with the blue background and the theme is easily recognizable.
An exciting headline is a nice complement to the graphics on the poster. Write a short message and give it a prominent position in the document, like in this example. Don’t forget to make it big and easily noticeable and choose some nice-looking font that works with the Christmas theme and the overall style of your poster.
Be sure to include the most essential information: where and when the party is taking place, if there are special guests, if people are required to pay an entry fee to get in and so on. Include contact details for additional information and for reservations (if applicable).
Christmas parties are exciting once you get there, but you want to get your guests excited before they get there!
-Article Source: http://www.printaholic.com/make-christmas-party-poster/