When designing a poster it is important to capture the attention of the viewer and also keep it simple enough so that they can get the information you are wanting to alert them to quickly. Having fun and interesting graphics and headlines helps to achieve that and then giving them clear direction on why they would be interested in your promotion and giving them an easy way to take action. Another great use of a poster design is to direct people to your social media pages where you can also have the poster set as a graphic on the welcome page and when they click through (ie facebook) to your page they can tag themself in the poster to gain entry to a competition for example. To see more ways in which you can integrate your offline marketing with social media click here Your Website in Facebook