To write a dramatic scene in James Joyce's "Araby," review dramatic structure...something that has been analyzed since Aristotle wrote.
In this case, however, you are looking for guidelines to write a dramatic scene, selecting a portion of the story: specifically when the narrator leaves "Araby" (the bazaar) without having bought a gift for Morgan's sister. This is very emotional for him—he sees life from a new and unsettling vantage point.
To write drama, look to Gustav Freytag's observations which are tools fo the trade in drama. Fretytag asserts that...
...a drama is divided into five parts, or acts, which some refer to as a dramatic arc: exposition, rising action, climax, falling action, and dénouement...
This "arc" requires an introduction (exposition), details that increase the sense of drama or excitement (rising action), the moment of the greatest intensity in the story (climax), counting the dead bodies or tying off loose ends (as might be the case in, let's say, Hamlet), and the resolution, the final word (the dénouement).
As an example, the climax is when the narrator sees the seedy side of the bazaar and is driven to leave without fulfilling his purpose.
Gazing up into the darkness I saw myself as a creature driven and derided by vanity; and my eyes burned with anguish and anger.
Lead up to this intense moment with growing excitement, conveying the narrator's driving desire to go to the bazaar.
Hopefully, the "arc" is familiar to you. To write a dramatic scene, break it down into these pieces—for there is the conflict in the story (which is necessary to every tale), so you can introduce all the necessary dramatic elements, "down-sizing" them to fit this specific scene.
Next, know your story inside and out, and know (understand) your characters—in this case, most especially the narrator—for this is his awakening, his "ah-ha" moment. (This is also called an "epiphany," which James Joyce popularized in his literature, especially in A Portrait of the Artist as a Young Man.) Don't just be familiar with your character—know who he is! This is what you establish in your "arc," without retelling the entire story: it must maintain its focus on the scene at the bazaar, and have only enough details to engage the reader's interest/concern for the narrator—to understand the context of the situation and care enough to read on.
Treat "Araby" like a story within a story. Use "word economy." Don't tell everything you know—it's boring. Tell the audience the most important pieces they need to know. E.g., how the narrator really feels about Morgan's sister.
There are other suggestions...don't describe what is happening—Tell it. Stay focused on your "tale." The elements of the "arc" are there even in this segment of the story.
Write, write, write! Once you have all the elements of the story, then edit, cut, and whittle down to the essentials: the elements of the story that drive the plot! To make the scene dramatic, it must be sizzling with action that draws the reader in:
...you must have dramatic material: heart-stopping events are required...
Chisel down even more, editing further. Only things absolutely necessary should be included—but include things the reader must know: bare bones writing, with excitement, focus and reading fulfillment—happy or sad.
These are the things I believe you must have to successfully write a dramatic scene.