With the assumption that you have many moments in your life when you wanted to be joyful, we will help you to make that a reality. All you need to do is to listen to advice.
Like most important advice, first you have to do is you should to know how to feel joyful for small everyday things. For example, try to feel joyful when you see clear sunny morning or when you hear the birds chirping.
Nature is full of beauty, and it is a sufficient reason to you should feel jouful. Apart from nature, the reason for this will give you the people around you. Many person loves you for sure, or you are simply important for them. It is a second sufficient reason for your joy and you.
Wherever you are, do not forget one thing, every external reasons on the world for joy, will not be enough if you do not have a enough reason and decision in self of you.
So, you try you remember the time when you were most joyful in your life, and try that feel make back.
Any your joy, will open the way for new joys, which are much stronger and greater than the previous.