Move a quiet, introverted person into sales and watch them struggle. Put an artistic, creative person into the Accounting Department and they will search for the few parts of the job they enjoy. Or if you select a process-oriented accountant for a marketing role, you won't get their best work. An engineer responsible for fashion design wouldn't be a good choice either.
So learn about your people. Find what they do well. Put them into situations or positions where they and their talents are needed and valued and they will bloom like flowers. Give them an opportunity to succeed and they will rise to it. That's not to say you shouldn't challenge them, push them a little, set goals that they have to stretch for. You should. Just make sure they are in the right spot first.
Here are some articles that explain how this can work for you: