What sparks your passion? Your readers often have the same passion and setting light to it keeps them satisfied and coming back to buy your books.
Decide what it is you want to evoke from your reader. Then fire your own feelings up, surprise yourself. Make yourself love, sing, dance, laugh, cry, grieve, gasp, shudder and scream. Make your heart race. Give yourself goosebumps. Make yourself so angry you want to punch something. Live your story. Feel every emotion as if you are each one of your characters.
Why? Because the odds are high that if you don’t feel those emotions, your readers won’t either. Find that unexpected match that triggers those emotions in yourself and odds are you will trigger them in your reader too.