Why does the Pasuk first say that the Egyptians saw Sarah and then, that the officers of Pharaoh saw her?
Seforno: First it was the people who saw Sarah, and as Avraham had suspected, they began planning to 'buy' her. But when Pharaoh's officers spotted her, they decided that she was fit for the king.
Ramban: The Egyptians initially thought that Sarah was worthy to marry into the aristocracy of Egypt, so they handed her over to the king's officers. However, when the officers saw her dazzling beauty, they were afraid to lay a hand on her, and decided that she was fit for the king himself. 1
As Rashi and Targum Onkelus explain. According to Targum Yonasan, they told Pharaoh about her and he took her himself.
Why did the officers not first consult Avraham, to talk him into giving them Sarah, as was customary in those days, before taking Sarah to the palace?
רש"י: הללו ביניהם: אולי הכוונה שהללו אותה בפני פרעה?
גור אריה: לא כתוב שפרעה לקח אותה, אלא "ותֻּקח האשה", ומכאן שהשרים הם שלקחו אותה אל פרעה.
גור אריה: צריך היה לכתוב 'ויהללו אותה לפני פרעה' ולא "אל פרעה", עיי"ש.