Huck often makes comments about his "store clothes" through the novel, signifying his discomfort in the trappings of civilized life. A majority of the commentary on Huck's "civilizing" takes place at the opening of the novel, but there are a number of other places where Huck makes remarks about his distress regarding civilized dress and comportment.
How about looking at a different way to show Huck's resistance to accepted norms and behaviors: through dramatic irony. Dramatic irony, of course, is when the reader or audience knows something that the character does not know. Although most people won't agree, the following incident is my very favorite part of the book. At first Huck seems to conform to the norms by feeling "free from sin" as he writes a letter to Miss Watson in order to turn his good friend Jim in as a runaway slave. Suddenly, Huck is bombarded with numerous memories of Jim being a wonderful friend and companion on the good ol' Mississippi. Huck can't take this kind of sentimental barage. Take a look at what he says, holding the letter in his hands:
It was a close place. I took it up, and held it in my hand. I was a trembling, because I'd got to decide, forever, betwixt two things, and I knowed it. I studied a minute, sort of holding my breath, and then says to myself:
"All right, then, I'll go to hell"- and tore it up.
There ya' go, ... going against the institution of slavery, ... I would call that a true departure from accepted behaviors in the deep South! Of course, as the audience, we know that Huck is doing the noble thing by not turning Jim in. It's an instance when Huck was actually taught the wrong thing by Miss Watson and others. Opposing an intrinsically evil aspect of Southern society, ... Huckleberry Finn, ... my hero.
I think the main place where we see it is in Huck's attitude towards slavery. Huck knows that he is supposed to agree with slavery and to look down on black people. However, he has a very hard time doing this. He would rather go against society and rescue Jim from slavery than be a "good" member of society and turn Jim in.
In responding to this question you might like to think about the way that Huck rejects Christianity in the novel because of the way that he feels it is presented. This is a major theme in the novel that is worthy of some attention, and we can see the beginnings of this in the very first chapter, through Huck's response to Miss Watson's attempts to civilise him and to make him a good Christian boy. Note how he responds to her efforts:
She said it was wicked to say what I said; said she wouldn't say it for the whole world; she was giong to live so as to go to the good place. Well, I couldn't see no advantage in going where she was going, so I made up my mind I wouldn't try for it. But I never said so, because it would only make trouble, and wouldn't do no good.
Here we see that Huck responds to Miss Watson's presentation of heaven as a physical place where she is going with the response that he does not want to go there, thereby rejecting Christianity in the form it is presented to him and going against one of the major cultural attitudes and customs of his day. You might want to extend this response by looking at Huck's attitude to Christianity and religion throughout the novel, especially when he decides to "go to hell" because he wants to rescue Jim.