Practice exposing your own feelings in short stories. Bring to mind experiences that were packed with emotion, both positive and negative, and write the scenes. Try to describe your feelings as you bring them to the surface. Notice your breathing, eyes, heartbeat and hands. Describe how the feelings impact your thinking and reactions. This type of practice is an excellent way to focus on the critical elements in the ways people experience emotions.
Re-read short stories, books or poems that have won important awards and recognition for the evocative power of their writing. Pay attention to how the writer positions the characters in peril to expose their feelings. Copy the first page of each of your selections by hand into a notebook to feel the words as they are being used. Sense the rhythm and patterns in the rise and fall of the words. Note the variations in sentence length and how the writer shortens and speeds up the writing as the emotions race toward a climax.
Ask yourself if your characters analyze their feelings too much in the moment of the story. Also note whether you are trying to manage or control your characters too much, restraining their spontaneous reactions. How you respond to a crisis is likely to be similar to your characters. Make one of your characters similar to a person you dislike and give yourself permission to imagine how that person would act in the scene you create for them. Allow the characters to be different from you, to have different ethics and motivations.
Find a few books you were unable to put down when you read them. Read through the first five pages to locate the exact spot you became hooked. Examine how the writer orchestrated that moment inside of you. Look for the techniques used to suck you into the character and the character's problems. Try to replicate the techniques in scenes that you write.
Write in the heat of the moment. As much as possible, write your first draft without revising or editing. Let your inhibitions run free. Get your characters in trouble and then make it worse, and then when it can't possibly get worse, make it worse. Struggle within a story is one of the strongest ways to evoke emotion. When a person is stressed, he or she will react and respond from their gut, without all of their conditioning. This is the meat that the reader wants to find. Give it to them.