So considering what i have done for this 2-3 years period, i want to share my experience regarding the proposal and RFP related project, which hopefully could help you in preparing better proposal and off course win the project.
In short that the key of successful proposal is not only rely on good layout/themes but also about good document structure, good 'direct to the point' style but it's all about the art to present the content in the way that people -in the end- will agree and moreover will buy or using your service.