What are the character traits of Bard?

Bard is a fairly well-developed character even though he enters the story near its end. There are a number of clear character traits and several more that can be inferred from the text. I’ll give you a few examples to get you thinking.
Bard stays until the very end of the battle of Esgaroth. His company has fled and he is down to his last arrow when the thrush finds him and tells him of the dragon’s weakness. This demonstrates that Bard is courageous. He is also proud, which we see as he comes back from the battle, declaring himself to be the slayer of the dragon. He does not, however, seem to be arrogant, since he defers to the Master of the town in the conversation that follows. Roac the crow declares Bard to be trustworthy when he speaks with Thorin regarding the approaching men, telling him to speak with Bard rather than the Master. And we see Bard fulfill that trust when he lays the Arkenstone to rest with Thorin after the battle.
We can infer that Bard is strong, as he draws a large bow, and that he is disciplined, because one needs much practice with such a weapon to become a good shot and captain of a company. You might also call him measured, as he seems to consider his words and actions carefully.
There are more traits to discover, but this should give you a good start.