Foundations appreciate those who take the time to gather all the facts, and they might even recognize your name when your proposal comes up for review. Pay careful attention on what to emphasize and what to tone down. Reviewing stacks of proposals is a difficult job. Grant reviewers quickly learn to scan text, particularly proposal abstracts, in an attempt to get a quick overview of exactly what you expect to do, with whom, when, how, and toward what measurable outcome. If you are short and to the point, and you've answered the key questions, your grant will be viewed as comprehensible and fundable.
Good proposals are easy to understand.
Remember they will want to proudly promote your project as one of their great projects. Good writing should be easy to read, understand and should present your ideas in an exciting, yet specific manner. The abstract of your proposal is the single most important paragraph of any proposal. You should know exactly what you're planning to do with their money, and express it in elegant simplicity. If the grant reviewer has a good idea of the direction of your proposal from reading the abstract, it creates an important first impression that you do indeed know what you want accomplish, with whom, at what cost, and specifically how.