Your development should follow the 70-20-10 rule:
70% of your development should come from on-the-job activities and action learning. This can include development experiences like managing a project, serving on a cross-functional team, taking on a new task, job shadowing, job rotation, etc.
20% of your development should come from interactions with others. This includes having a mentor, being a mentor, coaching, participating in communities of practice, serving as a leader in a staff organization, etc.