Most memorable fiction has a heavy emotional punch. The emotions can vary, although the best fiction is something of an emotional roller coaster and mixes some variety of “ohshitohshitohshit” with lighter emotions. The challenge is to have readers feeling those emotions along with your characters – that’s a skill that can take a while to build.
Building the ability to force empathy on your readers is why a lot of beginners lean to tragedy. It’s easier because grief is such a huge, terrible thing, and if you kill off the loved ones early it has the side benefit of leaving the protagonist damaged, unsupported, and without inconvenient connections (how often do you see authors do what Sarah did with Darkship Revenge and have their main character dealing with a newborn baby for the whole book? That’s not easy, not for the character and not for the author).
So how do you pull your readers into caring about your characters and feeling the emotions you want them to feel?
There are – as always – a variety of techniques that work. As the other here have mentioned many times, it works better to show the effects of the emotions than to just have the character crying, or smiling, or whatever. My preference is to describe the typical involuntary reactions to strong emotion, mixed with a train of thought indicating whether they’re welcoming said emotion or trying to fight it. Since I generally write in deep third or first person, this works for me. If I need readers to pick up on an emotional response for a character who isn’t the current point of view, I’ll show that character having the involuntary reactions – and depending on the needs of the story the point of view character will respond appropriately or not.
One thing I have found is that simple is usually better. In extreme situations, the ability to think complex thoughts tends to go the way of the dodo and be replaced with direct everything. I’ve learned to let my writing style reflect this by saving the love of wordplay and cute phrasing for the more relaxed times in the piece so the emotional punch of a story can be carried in simple, straightforward prose. Without the nested parentheses I inflict on y’all here.
Some of the best examples I can suggest are the climactic sequence of Sir Terry Pratchett’s Thud! – which had me somewhere between on the edge of my seat, laughing, and in tears, often within the same paragraph – Sarah’s Darkship Revenge, damn near anything of Dave’s (I’m particularly fond of Steam Mole for that), a goodly… oh, the heck with it. Pretty much all my fellow Mad Geniuses (Mad Genii?) do a damn good job of pulling readers into a story and dragging us through a powerful emotional ride. Pick your favorite, and reread it with an eye to how the emotional reactions are evoked. You’ll probably need several attempts before you can do that without getting sucked in because they’re just that good.
Then try to do similar things with your work. And practice. Lots. And give yourself permission to suck at it, because like anything it takes practice to get better.