Emotional scenes often come easiest and can be the heart of a story. I adore them. But it can also be hard to do a scene justice (messy first drafts are your friend here!), especially when editing, so here is my advice:
The first question I ask is, Why does my character care? If your reader has been with your character for a long time and knows the significance of what’s happening, they’ll know the stakes. It will matter to them by extension. And it usually works best if it’s something you care about too. “No tears in the writer, no tears in the reader.” — Robert Frost
Details and metaphors can both work in very different ways. When you’re being less direct and want the reader to bring in their own experience, a detail like a favorite object can be powerful. So can visceral details, like a character’s physical reaction to an emotion. But if you want to convey a very specific experience, metaphors can convey what physical details can’t.
Writing style itself can also convey emotion. Usually, short sentences and common words work best for emotional scenes, because your character won’t have the presence of mind to be all fancy and literary about it, and because we have stronger associations with common words. For example, the word pollen makes my eyes start watering in the spring (I have allergies), so my dad and I have started calling them “air floaties,” which has a less direct association with the thing itself. (At least for now.) On the flipside, using exaggeratedly sterile language conveys that your character is concealing their emotion, maybe even from themself. Within that, word choice and punctuation can correlate to specific emotions. Some of my associations are that happiness has a lot of exclamation points, understandably, though if it’s calmer it would be more likely to have longer sentences. More strong, charged words convey anger, as well as more sentence fragments, dashes, and all caps. Common words, sentence fragments, and unfinished sentences convey sadness. Clever, longer sentences convey a clearer head or that the character is concealing something else. A lot of this can be instinctive and depends on your style, but try experimenting with your punctuation and word choice when rewriting!
When writing emotional scenes, you don’t have to go overboard (it partly depends on your POV character). Overly drawn-out, emotional language can exhaust your reader and not leave them room to feel for the character. Instead, a single, impactful thought or detail can do more. As an example, it’s enough to just say, “She didn’t say goodbye” and not go into the following “Her cold silence hits me like a wall as a void opens in my heart where she used to be.” However, it depends on the style you want — a long, agonizing, heart-wrenching (or overjoyed or rhapsodic or impassioned) soliloquy has just as much place in literature.
Lastly, follow your heart. Whatever advice anyone gives you, if something feels right, it is. You are the only one who can tell your story.