What are some examples of Hermia's character traits from Shakespeare's A Midsummer Night's Dream?

One good place to find out about Hermia is in Act III when she and Helena are fighting. It makes for good comedy because of the names the girls call each other, but it also gives good insight into what each girl knows about her best friend. They use their close knowledge about each other to argue about their current confused circumstances; and one example of Hermia's character comes to light as follows:

"Puppet? Why so? Ay, that way goes the game.

Now I perceive that she hath made compare

Between our statures; she hath urg'd her height,

And with her personage, her tall personage,

Her height, forsooth, she hath prevail'd with him" (III.ii.298-302).

Hermia, therefore, is short. Hermia mocks Helena's (tall) height compared to herself because she was called a puppet. But we also see that Hermia won't back down from a fight. She flies at Helena fully intent to fight for herself until Helena asks to be released from Hermia's wrath.

Lysander, when under Oberon's spell, also gets in on calling Hermia short:

"Get you gone, you dwarf,

You minimus of hind'ring knotgrass made;

You bead, you acorn--" (III.ii. 340-342)

Hermia's other characteristics is that she is loyal to Lysander. She is willing to forsake her title, money, and family for him; which, in fact, is the reason they end up in the woods. She unsuccessfully elopes with him through the woods that night, which proves her loyalty to her love. She's also a good friend because she tells Helena about her plans to elope with Lysander partly so her friend knows Demetrius will be alone for her to pursue:

"Take comfort: he no more shall see my face;

Lysander and myself will fly this place.

Before the time I did Lysander see,

Seem'd Athens as a paradise to me.

O, then, what graces in my love do dwell,

That he hath turn'd a heaven unto a hell!" (I.i.205-210).

By leaving with Lysander, Hermia hopes to marry him, but she also helps Helena in the process because she's decided not to marry Demetrius. As a result, Hermia is not loyal to her father's wishes. In Hermia's day, she could be killed for disobeying her father as she does. Theseus tells her that she must either marrying according to her father's will, die, or go to a convent (I.i.120-124). Hermia is courageous because she chooses none of the above and hightails it to the woods. Luckily for her, the fairies make things right during the night and she suffers none of the consequences she faced beforehand.