This pops up all the time: someone wants to get better. They ask: what should I do more to get more focus and grow? The short answer you should give: do less.
As a leader, it is important that we help the people around us do fewer things, better. One option is to just pile up work and see how they handle it, but there is only so much one person can do.
Another route is to work together to see what stuff he or she can delegate, to free up time to focus and do even better work.