Resources
This presentation at the AEA Evaluation 2013 Conference by Artineh Samkian, the University of Southern California, and Joel Greene, Harder+Company, gives an overview of the steps involved in creating a graphic timeline that is accessible to stakeholders.
The highlight of this presentation is the number of examples of graphic timelines provided. The examples showcase a range of styles created for different purposes and audiences, while all drawing on and making clear the importance of the strong integration of colour, photos, graphics and text.
The First 5 LA timeline is examined in detail during various stages of production to highlight the steps involved in creating a finished product:

Source: Samkian and Greene, 2013
(Samkian and Greene 2013)
This presentation can be complemented by the AEA365 blog post of the same authors.
Sources
Samkian, A. and Greene, J. (2013, October 17). Visualizing Process: How to Create a Stakeholder-friendly Graphic Timeline of Process Data. Presented at the American Evaluation Society Evaluation 2013 Conference, Washington.
'Visualizing process: How to create a stakeholder-friendly graphic timeline of process data' is referenced in:
Method