How can I live more joyfully?

I believe that the world is a wonderful place full of opportunity, great things, and lovely people. I also believe that I am an efficacious person, and therefore capable of flourishing and achieving happiness. So why do my emotions not match my convictions? I want to live more joyfully; I adhere to the cardinal virtues to the best of my ability; I've tried mental exercises, such as listing all my personal values and thinking about how important and good they are for me, but it still doesn't make me feel happy. What am I doing wrong? What can I do instead?