How to make sure they are actually smart? Presenting with role specific tasks and then reviewing the homework thoroughly. It definitely proved to be an effective hiring strategy for Miner.
Another learning is time line management. Having a strict dead-line for each projects helps getting things prioritised. I.e. having a dead-line for the launch, helps to prioritise platform development, early adopters, website development work. Each of these project also have two cut-off dead-lines to allow time for revision & fine-tuning.