Joy

Perhaps the worst marketing for Christianity is joy-less Christians.
Joy
is evidence, or a result, of the presence of the Holy Spirit
(Gal 5:22).
But isn't Christianity serious? Yes! C. S. Lewis points out "Joy is the serious business of Heaven."
The faint, far-off results of these energies which God's creative rapture implanted in matter when He made the worlds are what we now call physical pleasures; and even thus filtered, they are too much for our present management. What would it be to taste at the fountain-head that stream of which even these lower reaches prove so intoxicating? Yet that, I believe, is what lies before us. The whole man is to drink joy from the fountain of joy.
Getting More
Joy is not a substitute for sex; sex is very often a substitute for Joy. I sometimes wonder whether all pleasures are not a substitute for Joy.
Ok, how can we get more, especially when life brings trials?
First, remind yourself of the big picture. On the eve of Calvary, in the face of severe execution, Jesus said, "in this world you will have trouble, but be of good cheer for I have overcome the world!" (John 16:33). He doesn't say we'll miss troublebut that in Him we overcome it. Be of good cheerin Christ you're a winner.
Second, practice delighting in your spirit over your circumstances. They are not the same! Two examples: a) When you are circumstantially challenged, you can still have a deep inner sense of well-being; and likewise, b.) When you are materially blesssed, you can still feel empty in your spirit.
In both cases something is going in the spiritual realm that is on a different plane than the physical oneit's in the spiritual realm that we find joy. (Material success makes us only "happy".)
Happiness vs. Joy
This may appear overly-technical, but there's a key point here. If you "be good" then you'll "feel good." And being good first happens spiritually. Peter Kreeft clarifies:
We can control happiness, but not joy. Since joy is often a surprise, those who insist on control will have more difficulty being joyful. Jesus said the only way to enter into the Kingdom of Joy is to receive it like a kid (Mark 10).
Happiness is in us; but we are in Joy. Thus we can have happiness, but not Joywe can only let it have us. We receive, not achieve. For this we must surrender.
Surrendering to Joy
I can only give you more when you take hold of less. I have abundance from My throne that only those who love Me from their heart can know.
Mine is a Kingdom of light and I shine where I am free to be steward, to call the shots and nothing short of total surrender will do. God is and always will be your source of hope. Don't pretend that this earth is capable of offering or providing a substitute. The earthly things only offer a reflection of Me for I created it all and am the source. How could anything created hold any real hope? Why cling to it?
You have no reason not to be joyful for My presence is Joy. I have conquered it all; I have won the victory; I know how the game ends and we have won. I call the shots in this life from Heaven. Remember all I do is infused with My joy and there is no cause ever for despair. Despair is so foreign to My kingdom; it is strictly the creation of man out of communion with the King of Kings. It does not exist in Heaven, your true Christian home. In essence, it is not real, only real to the extent that you include it in your realm. Do you not exist in the Heavenly way when all is said and done? Keep ever focused on Me and you, too, will never know desperation.