If possible, arrange pitching of concept ideas, preferably shortly before the submission deadline.
A structured and open pitching - in front of students and teachers and a panel of ‘simulated experts’ - is highly motivating and rewarding. It is pitching-training, but indeed it also improves the concepts and the final submissions.
(Suggestion for a pitching model: Let the students define their own panel well in advance, i.e. to whom they would like to present their concept. The panel then pretend to be these ‘real’ experts, e.g. a potential customer, a media organisation, an investor. With students and teachers as a silent audience, the pitch consists of presentation and questions, and with a feedback afterwards on both concept and performance.)