Where a scene is located in the story structure, what role it plays, and whos tells that section of the story are important elements in deciding how to craft a particular scene.
Positioning
Opening scenes should introduce characters, set up the story premise, and give hints at backstory. Don’t go overboard on any of these elements. Orient the reader, and fill in the details later in order to avoid overwhelming the reader with too much information or names to remember.
Middle scenes should continue to introduce and work through complications, provide twists, and increase the stakes. These scenes contain the bulk of the story. They should build on each other and provide story progression. Scenes that lag or lack clear purpose should be eliminated or revised to prevent the reader getting bored.
Climactic scenes will build to a climax, and are typically toward the last third of the book. They are often shorter and use high levels or emotion and action. Be careful not to string too many climactic scenes together. This can overwhelm the reader. Give the reader a break every so often with scenes more focused on recovery, discovery, or introspection.
The tone, feel, and purpose of a scene should correspond to its place in the story.
Purpose
Every scene must have a purpose. That doesn’t mean that every scene needs action. Purposes might include advancing the plot, revealing something about the character or world, or providing information about the overall plot, highlighting change, etc.
For writers who outline, it is usually easier to make sure each scene will have a purpose before it is written. For pansters, this may be more challenging, because you don’t always know where a scene is going when you start writing it. Pansters need to revise critically to make sure there are not superfluous or meandering scenes.
The purpose should be able to be condensed into a one sentence summary. For example, This scene will show David blowing up and scaring Emily away by proving to her that he can’t control himself. If a scene doesn’t have a purpose, it likely doesn’t need to be there or need to be revised with a stronger focus on accomplishing something relevant to the story.
Point of View
It is important that a scene be told from the most impactful point of view.
This is usually the character who is most impacted by the events of the scene. If you find that emotion isn’t coming through in the scene like you wanted it to, reevaluate whose POV it’s being told from. Think about what the stakes are for each character involved and who has the most to gain or lose by the outcome of the scene.
POV is often tied to the purpose of the scene. Make sure you have a firm purpose and then evaluate who will learn the most, change the most, react more strongly, risk the most, etc.
There are exceptions, of course, often stylistic ones. If the emotional elements are so strong they may impact the reader in a negative way or be overwhelming, writing the scene from a peripheral viewpoint might be a better option. This may be the case with traumatic experiences or a particularly gruesome encounter.