Is the assignment /project consistent with the learning outcomes for the class? Have you adequately communicated to the students how it fits into the large context of the class?
What skills must be demonstrated in the completion of the assignment? How much (if at all) does it engage student creativity?
How realistic is the level of stringency of the assignment? Are the students equipped with the expertise to handle it? (Don’t give freshmen a senior level project and expect success.)
How clear have you made your expectations/criteria for grading? Do you have a specific ‘vision’ for how the project should turn out? Have you communicated this to your students?
How realistic is the time-demand of the assignment? Remember that they are taking other classes, too!