A sustainable development strategy is a continuing and adaptive process of strategic and coordinated action.
Fifteen years ago, Agenda 21, the United Nations' call to action for sustainable development, envisaged that the necessary harmonization and extension of existing policies and plans would occur through the adoption of an identifiable strategy for sustainable development. Rather than develop a new strategy document, the overall objective was "to improve or restructure the decision-making process so that consideration of socio-economic and environmental issues is fully integrated and a broader range of public participation assured (paragraph 8.3, Agenda 21 – UNCED 1992)."[1]
A sustainable development strategy is not simply a document. It's a continuing and adaptive process of strategic and co-ordinated action (Figure 1). It has been described as:

IISD continues to research and communicate innovative practices in sustainable development strategies to government practitioners around the world. Two such studies are:
National Strategies for Sustainable Development
In this international and collaborative research project, strategic and co-ordinated action toward SD taken at the national level in 19 countries—before and after WSSD—was researched.
Governance Structures for National Sustainable Development Strategies
IISD was commissioned by the Organisation for Economic Co-operation and Development (OECD) in 2006 to study approximately 20 countries to identify good practice examples of governance structures for the National Sustainable Development Strategy and to study their effectiveness.
[1] paragraph 8.7, Agenda 21 – United Nations Conference on Environment and Development 1992, Available at http://www.un.org/esa/sustdev/documents/agenda21/index.htm; as cited in Cherp, Aleg, Clive George and Colin Kirkpatrick. 2004. A methodology for assessing national sustainable development strategies. Environment and Planning C: government and policy 22 (2004), 913-926.
[2] Dalal-Clayton and Bass (2002). Sustainable Development Strategies – A Resource Book. International Institute for Environment and Development. London: Earthscan Publications Ltd.
[4] Steurer, R. & Martinuzzi, A., 2003. Sustainable Development in an enlarged Union: Linking national strategies and strengthening European coherence. Good Practice Guide, p.16 Available: http://www.nachhaltigkeit.at/lisstra. In Steurer and Martinuzzi, (undated) "Toward a New Pattern of Governance: First Experiences with National Strategies for Sustainable Development in Europe," Vienna University of Economics and Business Administration.