1. Don't be afraid to show real enthusiasm. Stammering or not. 2. For the design question, they're looking at your architecture skills. You already have a list

1. Don't be afraid to show real enthusiasm. Stammering or not. 2. For the design question, they're looking at your architecture skills. You already have a list of these questions, so just try to solve them in your own time. Look at how existing ones are architected. Try to design them cleanly etc.