Without organization, the project will be jumbled and useless. The viewer should be able to navigate information that is otherwise overwhelming.
It should evoke strong senses of the reader. Some connection between the user and the material should be cultivated. Visually, it needs to draw the user in, and substantially needs to provide the information that compliments the aesthetics.
If it’s not interesting, why bother? The user should be entertained and drawn in by the visuals and the subject material.
This branches from entertainment value. A good DH project should not divorce entertainment from education, but the educational component is important in and of itself. The purpose of the project ultimately is to educate and to make that education accessible.
The subject must warrant examination. Why does this information deserve to be made into a DH project? Not all project ideas are worth the effort.