"He could be my brother. Straight black hair, olive skin, we even have the same grey eyes." (page 8)
this quote describes Gale's physical characteristics of "straight black hair, olive skin, and grey eyes." It also describes how similar Gale looks to Katniss, and how it looks as if they could be related.
Gale will get her the herbs she doesn't grow herself, but she must be careful to describe them because he's not at familiar with them as I am. He'll also bring them game-he and I made a pact about this a year or so ago-and will probably not ask for compensation, but they should tank him with some kind of trade, like milk or medicine." (page 35)
This shows Gale's selflessness and how he cares for the survival of those close to them. It shows that he is willing to provide for others even if there is no benefit for himself.