It might be hard as a manager or team lead, to get your team to make room for creativity. Aviv Ben-Yosef has some tried and tested rules to make sure it happens.
After communicating major milestones, your team can choose other goals they wish to accomplish. If they are hitting every mark, that means they aren't dreaming big enough. Make sure to push the team to dream bigger, but evaluate the risks of their actions. Reward experimentation even if it doesn't pay off. To improve next time, they should retrospect and look for causality instead of placing blame.