If value is the source of joy, how do we increase value? By increasing desire and appreciation. These things come from our perceptions. They can be informed by observation, by introspection, by choice, and by experience.
Jesus said:
Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you. (Matthew 7:6)
A pig’s primary concern in life is to eat ravenously. They do not want pearls. They want slop. Slop is far less valuable than pearls, but they don’t know that. Pigs do not value pearls any more than dirt. Dogs are similar. Animals do not perceive value in even the most valuable things. To them, all experience is reduced to a narrow band: something is either food or not, and most things that should not be food are still considered food (dogs eat vomit, pigs eat anything).
By default, humans are animalistic in their recognition of value. Instead of joy, we seek pleasure. Instead of lasting benefit, we seek what can titillate us here and now, without regard to future penalty or risk. Jesus said:
45 Again, the kingdom of heaven is like unto a merchant man, seeking goodly pearls:
46 Who, when he had found one pearl of great price, went and sold all that he had, and bought it. (Matthew 13)
Merchants spend their career learning the value of things. They buy things for less than they are worth and then sell them for what they are worth. They make their living by repeatedly trading everything they have for something more.
By default, humans are poor judges of value. They do not learn to discern between good and evil. They do not know the true cost of things, and they do not know the true value of things. They do not realize that what is better always requires more than what is worse.
Jesus said:
Again, the kingdom of heaven is like unto treasure hid in a field; the which when a man hath found, he hideth, and for joy thereof goeth and selleth all that he hath, and buyeth that field. (Matthew 13:44)
By default, humans do not know the difference between a normal field and a field that contains a treasure. They do not seek for hidden treasures, and only see the surface of the fields. They do not seek to see things in a different, more accurate light. They do not seek to differentiate between the commonplace and the valuable.
It is incorrect to think that what will bring you the greatest joy will be obvious to you or easy to obtain. It will be neither. By default, you are like a pig who can’t tell the difference between pearls and slop, a novice merchant who misjudges the value of things of great worth, and like a farmer who has no interest in seeking buried treasures in seemingly ordinary fields.
Joy comes from value. It isn’t intrinsic. There is no such thing as something that is equally valuable to everyone, because value is dependent on perception, and perception varies.
Value does not come from the price paid for it. Rather, it comes from what you get out of it. You can get something for free and value it highly, and you can pay dearly for something and feel it is worthless.
Value comes from the use you can derive from something. An expensive hammer and an inexpensive hammer could have inverted values if the inexpensive hammer works better than the expensive one.
Life is just as much about gaining the perception to value what God values as it is obtaining what God values. When you don't value something, you can't have joy. Adam and Eve dwelled with God in Eden, but because their lack of experience prevented them from valuing what they had, they did not know joy until after they were ejected from his presence.
It is easy to take for granted the valuable things we are constantly showered with: “And your minds in times past have been darkened because of unbelief, and because you have treated lightly the things you have received...." (D&C 84:54) Yet, these “small and simple” things can be critically valuable:
6 ...by small and simple things are great things brought to pass; and small means in many instances doth confound the wise.
7 And the Lord God doth work by means to bring about his great and eternal purposes; and by very small means the Lord doth confound the wise and bringeth about the salvation of many souls. (Alma 37)
Several scriptures describe the unimaginable magnitude of the good things God is willing to give us:
But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. (1 Corinthians 2:9)
For since the beginning of the world men have not heard, nor perceived by the ear, neither hath the eye seen, O God, beside thee, what he hath prepared for him that waiteth for him. (Isaiah 64:4)
Why are these blessings so difficult to describe? Why have they not been heard or seen?
One reason is because we do not yet have the perception necessary to recognize these things as blessings, even if they (or their precedents) are all around us. In other words, were you to describe it to a person who has not obtained it, they would just see those events as very normal.
There isn't anything in heaven that doesn't have a precedent here. It is quite easy for God to say "you know that thing? That thing here is just like this other thing in heaven. That is the sort of thing that awaits you if you love me." But he doesn't do this often, or rather for many people. Or for hardly any.
Paul knew many of these things. He had been there, after all. He could have given a sermon on the things he knew, but he didn't. Instead, he said “eye hath not seen,” etc. Why? Because when you tell people these things in plainness, they don't understand them or worse, they reject them, because these things, whatever they are, don't match their preconceived notions of what heaven ought to be like. They do not value the true qualities of heaven like those in heaven do.
Obtaining maximal joy requires obtaining those things that have the ability to deliver maximal joy and learning the value of those things. Having only one of these two requirements is insufficient to produce maximal joy.
Part of the purpose of the gospel is to help us establish a more correct valuation of things that are available here. By default, we place great value on carnal things that actually have very little value when seen in the context of a greater understanding of reality. For example, a child finds a piece of candy immensely valuable. An adult finds a first-world home immensely valuable. An elderly person finds independence immensely valuable. In the scope of things as they really are, each of these things and many more besides have very little value. By default, we place very little value in things that are actually good: honesty, unconditional love, patience, service, etc. As greater degrees of reality are revealed to us, by suffering if need be, our valuations adjust to be more accurate.
The gospel reveals hidden levels of sorrow and joy in “normal” life. It increases the depth of our awareness in knowledge, but also in emotion. If you asked one who loves God what their happiest moments are, they would start with something that just happened in the last few days because their happiness steadily increases through time, and they would also describe things that to you would seem quite normal. Perhaps they would be overcome with joy at remembering a momentary interaction with one of their children, or finishing a challenging but seemingly mundane task at home or work.
Awareness not only increases the amount of joy you experience, but also increases the quantity of joy you find in things you are already aware of. One New Testament story helps illustrate this principle:
36 And one of the Pharisees desired him that he would eat with him. And he went into the Pharisee’s house, and sat down to meat.
37 And, behold, a woman in the city, which was a sinner, when she knew that Jesus sat at meat in the Pharisee’s house, brought an alabaster box of ointment,
38 And stood at his feet behind him weeping, and began to wash his feet with tears, and did wipe them with the hairs of her head, and kissed his feet, and anointed them with the ointment.
39 Now when the Pharisee which had bidden him saw it, he spake within himself, saying, This man, if he were a prophet, would have known who and what manner of woman this is that toucheth him: for she is a sinner.
40 And Jesus answering said unto him, Simon, I have somewhat to say unto thee. And he saith, Master, say on.
41 There was a certain creditor which had two debtors: the one owed five hundred pence, and the other fifty.
42 And when they had nothing to pay, he frankly forgave them both. Tell me therefore, which of them will love him most?
43 Simon answered and said, I suppose that he, to whom he forgave most. And he said unto him, Thou hast rightly judged.
44 And he turned to the woman, and said unto Simon, Seest thou this woman? I entered into thine house, thou gavest me no water for my feet: but she hath washed my feet with tears, and wiped them with the hairs of her head.
45 Thou gavest me no kiss: but this woman since the time I came in hath not ceased to kiss my feet.
46 My head with oil thou didst not anoint: but this woman hath anointed my feet with ointment.
47 Wherefore I say unto thee, Her sins, which are many, are forgiven; for she loved much: but to whom little is forgiven, the same loveth little.
48 And he said unto her, Thy sins are forgiven.
49 And they that sat at meat with him began to say within themselves, Who is this that forgiveth sins also?
50 And he said to the woman, Thy faith hath saved thee; go in peace. (Luke 7)
This man Simon had invited Jesus to his home in spite of the negative press it would bring. And yet, Simon appreciated Jesus far less than the woman who was also present. Jesus had power to forgive the sins of both Simon and the woman. While forgiveness was of equal objective value to both these people, the woman was far more appreciative of that value than Simon, because she was much more aware of what it would mean to have it.
Likewise, you probably take a great deal of what is offered to you for granted—whether you presently have it or whether you merely have the means to obtain it. Central to your quest for obtaining greater joy is obtaining a more accurate valuation of what you take for granted. What is common to one is a treasure to another. What is mundane to one offers supernal peace to another. What is boring to one is infinitely interesting to another.