Pair up with someone and review each others' 150 Tons first submission. Then, provide feedback to each other (this can be in writing or via Skype). When providing feedback, practice "plussing," where you build on any criticism with new ideas that address the criticism and improve the project. In other words, don't identify a problem without also offering a solution. Don't just say "I don't think anyone will buy your innovation." Also add, "But, if you could reduce the price and target younger customers you may have a market."
In the discussion forum, share at least one improvement to your 150 Tons project that came from the feedback you received.
Can't change a rubric once you've started using it.