The National Institutes of Health (NIH) has released numerous podcasts since 2010 on preparing a grant application. This includes many podcasts focused on writing different kinds of proposals. Although the main focus is on NIH, many of the tips are universal. There are also transcripts of the podcasts, if that’s more convenient.
NIH put together “before and after” examples demonstrating how to make proposal text more concise and clear.
This guide from NIH offers tips for most parts of the proposal creation process. The end of the guide includes more than 20 bulleted tips concentrating on proposal writing.
Step two of this guide from the National Science Foundation (NSF) includes information on writing a proposal. The information is fairly general, but it could be of use to researchers new to sponsored funding.
This handbook includes tips on writing a grant proposal beginning on page 31. These tips cover contacting an agency, writing to your audience, when to begin writing, and proposal revision.
This paper provides baseline advice for writing proposals.