Joy is an inner feeling. Happiness is an outward expression.
We experience unhappiness because we buy into thoughts and beliefs about the current situation or stimulus that are counter to our true nature. It is never the situation itself that causes us to be unhappy – it is our interpretation of the situation that causes us to be unhappy. 
Joy is deep inside of us, but we can choose to keep it down or let it rise up within us. So, the other key ingredient is making the joy of the Lord our strength.  That is a choice. If we want to do things in our own strength, He will let us. Then we need to ask ourselves the question, how’s it working out? God is all powerful and the only time we have that power is when we yield to his will, not ours. Jesus said in the garden, not my will but your will be done. God’s will for our life is always the best. It may not seem that way at the time, but it is. We can make a mess of things sometimes. 
It all begins with love. The more we are consumed with his love and the more we love ourselves and others, a chain reaction begins where joy, peace, patience, kindness, generosity, faithfulness, gentleness, and self-control come forth in our lives.