As Michelle Obama notes in Becoming, First Lady is a role without a job description. How did Mrs. Obama choose to approach the role?

The epitome of grace, the former First Lady handled the job by holding tight to those things most important to her and by assembling a team of like-minded and trustworthy people.
Mrs. Obama knew that she would need help in transitioning herself and her daughters to the White House. She enlisted the help of her mother for this monumental task, and when her mother balked, she asked her brother Craig to convince her. Her mother "refused to get put into any bubble," declined Secret Service protection, and insisted on slipping out to the local CVS through a back gate. But her presence was reassuring to Mrs. Obama and their family, better enabling her to do the work required of the First Lady.
She also realized that she had to become accustomed to things being a little awkward because of her new position. She notes that she had to consciously work her way past the awkward experience of being in the presence of the Queen, and that she immediately liked her after getting over this. When dealing with her children, she felt the awkwardness in having to obtain Social Security numbers from all adults driving their kids over to the White House to play, but she realized that it was all necessary. Mrs. Obama didn't allow her own feelings to compromise the work that she knew she needed to do.
Mrs. Obama also listened to her intuition. When she surveyed what she could do at the White House to make it "feel less elitist and more open," she decided that she needed to plant a garden to "spark a public conversation about nutrition, especially at schools and among parents, which ideally would lead to discussions about how food was produced, labeled, and marketed and the ways that was affecting public health."
And Mrs. Obama stayed grounded in her daily life with her family. She loved being able to look out the window of her dressing area and see into the Oval Office so that she felt connected to the work her husband was doing there. She cherished that he could often join them precisely at 6:30 for dinner, which they had missed when he was a senator. She joked with her husband about his tidy appearance, telling him that "you get no credit for any of it" due to the assistance of his staff. She seized moments to get away with him to places like Times Square to watch a drama set in Pittsburgh.
Mrs. Obama blended her passions, work ethic, sense of family, and realistic approach to the history of our nation as she gracefully navigated the work of being the First Lady of the United States.