A study by JPL showed that two thirds of errors were due to incorrect or unclear requirements. By keeping data modelling out of the issue, you simplify the business specification process, and also prevent shackling your data-modellers with decisions made too early. I mean to look around for columns or groups of columns that will be commonly used around your site. Surnames, for example, should all be the same length. Addresses are an example of a group of columns that should be consistent, and with a set of packaged functions developed to deal with them.
Personal names are another common domain made up of a group of columns.
Anyway, these columns and associated functions should be tested, documented, handed to a librarian, and the information on them propagated to all developers so they don't go around re-inventing the wheel. Because these entities are simple, they are easy to implement. These early screens, having simple logic, let you sort out the look and feel of your application, and get approval from the users. They are also ready for plugging in to the next layer of screens dealing with the more complex objects. Each step inwards is resting on a solid base - the more you get towards the centre of your data model, the more complex things get, but the references are already in place.