This expression indicates which one of the two groups a particular person/thing belongs to. The two groups are compared in terms of the degree of their attributes. The speaker gives a certain description about the person/thing, but s/he does not think the degree is extreme.
わたしは兄弟の中で太っている方です。
I'm relatively fat among my brothers [and sisters].
アリさんはクラスの中で背が高い方です。
Ali is one of the taller students in the class.
マナさんは日本語が上手な方だと思います。
I think Mana's Japanese is above average.
Lesson 14(Dialog)「あの人のほうを見なさい。」
Look toward her.
Lesson 18-8「東京のほうが人口が多いです。」
Tokyo has a larger population.