When writing emotion, it's easy to become stuck on how to express what the point-of-view character is experiencing. An exercise to try is to pull from your own memory if you feel comfortable doing so. Sit back in your chair, take a few calming breaths, and think back to a time where you experienced this same emotion. Carefully draw up the memory, thinking about the situation, the location, the people involved. Remember the sights, sounds, smells, textures, tastes.Now, pay attention to your body. Are you relaxed, or tense? Are your muscles tight? Is it easy to breathe, or do you feel restricted? Is your posture curling up, an attempt to hide, or are you twitchy all over and want to leap out of the chair? Make as many notes as you can, and when you go to write, use what you collected to give life to the character's experience.