The first characteristic of a successful proposal is the degree to which the contents of the document respond to the specific call for proposal (CFP) that elicited it. CFPs are published by individuals and organizations wishing to receive a variety of project proposals. The CFP articulates the parameters of the proposal, including time line for completion, budget and, most importantly, the specific problem the person or group needs to have solved. When writing your project proposal, a good hint is to review the language of the CFP, particularly the key terms (buzzwords such as "interdisciplinary," "inexpensive" and "technical," for example), and reuse those words within the sections of your proposal.
Readers and reviewers of proposals approach the document with a set of common questions in their heads. The most important of these questions include, "What is the point of this proposal?" and "Why does this proposed solution matter to me?" Adequate, consistent and persistent responses to these questions throughout the proposal is another characteristic of a successful proposal. Though specific sections of a proposal (introduction, problem statement, conclusion) respond directly to both questions, a good hint is to always frame each section of your proposal around the "what is the point" question, and then hammer home your response to the "what does it matter" question in the concluding sections.
Because proposals are often highly technical documents, the layout and design of the document should be simple and crisp, so as to not interfere with readers' attempts to understand the material. Some characteristics of a simply designed proposal include clearly formatted section heads, standalone paragraphs (paragraphs that have a space both before and after them) and supplementary graphics (charts, pictures, graphs). When designing your proposal, a good hint is to circle and draw lines around all the individual components in early drafts of the proposal. This will break the format into chunks so you can ensure that different page components are properly spaced and laid out.
Maintain a reader-centered approach when composing and designing your proposal. In addition to concerns pertaining to the anticipation of common questions, as well as layout and design issues, writing should be framed in such a way that it appeals to the sensibilities of the reader. To compose your proposal using the reader-centered approach, a good hint is to research the would-be readers of your proposal so as to identify their specific goals. You should work these goals into the sections of the proposal, just as you incorporate language from the CFP throughout your proposal.