Think about the visual symbols of your theme and do a brainstorming session. For example, if you want to create a zoo-themed series of posters, you might select images of different animals found in zoos, photos of children visiting the zoo or by integrating animal type markings into your text and background design. Additionally, during this stage of the process you should look at types of papers on which you'd like to print, fonts you'd like to use and matters of poster distribution.
Make some rough sketches of your preliminary ideas. These sketches not only offer you the opportunity to see how your visual elements work to support your theme, but they also allow you to work out any difficulties you might face with composition, font or other design elements. Make sure that you do mock ups of potential photographic details you'd like to appear on your theme poster as well. These do not have to be works of art, but should give you some visual sense of how these elements will work together on your poster.
Create a workspace on your computer in which you'll keep all your visual materials. This should be a folder that you won't lose, put in a place like your "My Documents" folder on your computer.
Take photos of anything you for which you don't already possess photographic materials.
Import your graphic materials onto your computer and save them in your poster folder. A number of options present themselves in this regard. You can use the cable that came with your camera to import the images or use a flatbed scanner to scan your photos into your file folder.
Open up your design program.
Layout your images in your image creation software. You'll do this in accordance with your design sketches. While many designers opt for programs like Adobe Photoshop or Quark to accomplish this, you can also use programs like Publisher.
Add textual elements to your design. You want to select font sizes and types that people can read easily. Also, some design programs like Photoshop allow you to enhance fonts with decorative elements like animal prints. For example if you're working on the zoo theme mentioned earlier, you can decorate your fonts with animal prints. This helps to further support your poster's theme visually. (See "Resources" section for link).
Prepare your theme poster for printing by saving your poster in PDF (portable document file) format. You can then burn this file onto a CD and take it to the printer's for printing.