I'm also working on sadness, and I've so far come up with several points that contribute to creating the emotion. Tone -- Use words with negative connotations, like Never, Regret, Apology, etc. Style -- Your style of writing, the patterns you use, the techniques, devices. Like, allusions to Romeo and Juliet might stir up sadness. Subject -- The topic can be inherently sad, like death, break ups, bad grades, etc. Pacing -- You have to develop emotions through time. People have to be emotionally connected to a character to feel sad for him.
