Developers that won city data competitions and were interviewed by Government Technology had the following advice to offer city agencies:
Provide data that is in a standardized format, such as the General Transit Feed Specification standard. Providing data sets that fit standards encourages the development of national scale applications, which are easier to monetize for developers. Developers will still develop applications that use data sets that are not in standard forms, but it discourages the use of the same app for multiple cities. If developers find the data valuable enough, they will develop around the inconsistencies or someone will sell a standardized version of the data.
Verify the accuracy of the data before posting it. One of the developers interviewed suggested that agencies use software that does it automatically to remove the tedious process of manual verification, which can lead to backlogs of data updates. The need to "clean up" the data can discourage developers from using the data set.
Plan and budget for the continued provision of open data. Many of the developers cited the lack of data updates as a reason for no longer maintaining their applications, since the data the applications used is either no longer available or out of date.