Whether you want to protest a politician, a businesses policy, or create a banner that supports one side of a debate on a social issue, designing a protest banner is not a difficult process. The banner can then be printed out to fit your size requirements.
Brainstorm your message and design premise. You do not have space for very wordy messages, so think of phrases or slogans that might be appropriate, along with matching images. An effective banner uses a slogan or phrase that resonates with the public. Because your group intends to conduct a protest, have a meeting in advance and collectively brainstorm concepts that will work best for your banner. Also create some initial sketches using a sketchbook and coloured pencils. Remember that the primary goal of your banner is to get a message across, so avoid getting too "artsy" or using any phrases or slogans that might be considered in bad taste or outside the bounds of civil debate.
Create your final design in a graphics program as basic as Microsoft's Office Paint or as professional as Photoshop. While you can make a handmade banner, designing and printing your banner using a graphics program will create a more effective presentation that attracts attention and has your message taken seriously.
Open a new document and choose a background type, such as a transparent background. Set you banner's size as well as your resolution to at least 200 pixels for quality printing. Save your document in the proper format, such as a jpeg or png, but check with your printer to see if they have a preference. Usually for a banner, you should choose a transparent or white background.
If you plan to only use text, then choose a font that is easily readable from a distance and place your text on a layer. You may want to separate two or more different bits of text on individual layers. For example, you can have primary text in large lettering centred in your document, while a smaller section of text with your organisation's name and website address is placed below. If you are adding graphics, including photographs, these too should be placed on separate layers so that you may make changes to each element without effecting elements on other layers. Once you are satisfied with your overall design, save it.
Have your design printed. Consider having your banner printed through a site like CafePress, which offers high quality banner printing. Using CafePress, you may simply upload your image into their system. Read their policies and requirements for uploading images for printing. Additionally, many office supply stores like Staples also offer a banner printing service as well as a designing service. If, on the other hand, you are in a hurry, your best option for printing will often be a local printer in your community.