What's worked well for me...
Cross pollination among the people team. Understanding the long term aspirations of team members and letting each other work with each other (with guidance) to enhance actual work exp. In doing this, those who need further coaching & new skill dev, take up courses in their own (reimbursed) and come and implement learnings. You can't force this,those who want to learn, learn on their own - you have to help them along the way.