Apart from making sure that your learning object works technically (accomplished via testing) , you also need to ensure that your learning object is usable.
Usability testing involves watching actual users use your materials and understanding how the design either helps or hinders their movements.
We keep a set of links to resources about usability in general at http://www.wesleyan.edu/its/web/usability/selfserve/index.html.
Techniques for Reporting Results of Usability Analysis
We use a range of techniques for capturing information about how users interact with a given resource that we then share with the designers and developers. Examples of these reports are available at http://www.wesleyan.edu/its/web/usability/reports/index.html.