Many online resources exist with sample data management plans, some of which are from actual successful proposals. Take a look at the examples below to get a better understanding of what a DMP should include.
Your data management plan is both the place to start creating good data practices, and potentially a requirement of your grant. If you're creating a data management plan to meet the demands of a grant or agency, the first place to start is with their resources and requirements. The tools below will help translate requirements into a usable document.
DMPTool is an excellent place to start. This comprehensive, easy-to-use, open-source tool guides you through a developing a data management plan tailored to your needs that you can easily export. You'll create an ID and password, so your plan will stay private. Step by step instructions let you target your plan for a particular granting body. You can also browse an index page with sample plans, templates, and guidance.
This Primer on Data Management [PDF] from DataOne covers, in 10 pages, the basics of data management, including the life cycle of research data, best practices for collection, description, and preservation, and how to consider data management in the larger scheme of your research.