Some Cayce quotes to get you started:
Thus ye may find in thy mental and spiritual self, ye can make thyself just as happy or just as miserable as ye like. How miserable do ye want to be? (2995-3)
Let no day then pass that ye do not speak a cheery and an encouraging word to someone! And ye will find thine own heart uplifted, thine own life opened, thy love appreciated, thy purposes understood. (1754-1)
If the problems of the experience today, now, are taken as an expectancy for the unusual and that which is to be creative and hopeful and helpful, life becomes rather the creative song of the joyous worker. If the same problems become humdrum, something to be fought through, something to be questioned as to their purpose, their activity, their usefulness in the experience, then the life becomes rather as a drone, as of one drudging, coming through toil, and with only turmoil and a vision unclaimed, unactive in its associations with the general conditions of the day. (1968-5)
… happiness is love of something outside of self! It may never be obtained, may never be known by loving only things within self or self's own domain! (281-30)
Happiness, then, is not a thing set apart from self, but the conditions with which one approaches that in hand to be done! for when one considers that the position of self is hard to bear, is not as is desired, the desire of the heart often maketh one afraid – unless that desire is ever in that attitude of "Use me, O God, as I am," for the I AM is ready, willing, to make my will one with Thy will … (5563-1)
Happy are they that know the Lord in their daily lives. Not unto self-glory, but just being willing for self and self's abilities to be used even as He – "Not my will but Thine, O God, be done in and through me." Think ye that Jesus went happily to the Cross, or that He went happily from the garden where there had been apparently so little consideration by those of His followers as to what the moment meant? when they slept as He wrestled with self in the garden? Think ye then on thine own disturbances that are of the moment, though ye may have them in thy consciousness constantly, and worry as to this or that, the shortcomings of those ye love. How was He with those He loved? Yet He gave them his blessings. So in Wisdom, so in Happiness, bless them that despitefully use thee, that speak unkindly, yea though they deny thee of that thou knowest is thy part, even in the daily experiences. Bless them if ye would be Wise, if ye would be Happy or if ye would have Happiness in thine own life. (262-108)
(Q) Why did I have such an unhappy childhood?
(A) Happiness is a state of consciousness. It is found within self. Ye had not found thyself, nor thy relationship to the Creative Forces as may manifest in this material world. (2982-1)
Happiness is abiding in the Infinite love. Then to each individual here there comes the necessity of making Infinite love compatible with the material surroundings day by day. Hence we will find that it is as the Master gave, first keeping self out of the way, less of self, more exaltation of the Father-God, more patience, more kindness, more gentleness, more brotherly love. These, as you all say, we have heard before. Have you put them in practical use day by day? … Happiness then is knowing, being in touch with, manifesting in the daily life, DIVINE love…. Happiness is the love of God made manifest by those who love God's ways. (262-109)
You each will find, if it is but applied, that which will enable you to give to others a greater vision of what and how Happiness may be in the experience of others; and – as doers of the Word and not hearers only – become more and more in accord with that which has been designated as true Happiness.
To be sure, many find the inclinations for quiet or rest, or laziness, to become oft your metre or standard; but these, too, are – as has been given – far from true Happiness. For Happiness is being busy about the Lord's work; not in other peoples' business, not in that of stirring up strife, but rather as He brought to the world that of peace and Happiness in going about doing good.
That is the business, that is the activity, that is being doers of the Word; that is showing forth faith by the works.
In this then, let you each arouse yourselves to that which will enable you as individuals to give in your daily dealings with others a greater expression of joy, and not of those things that build for offences of one nature or another.
For offence is absent from joy or Happiness. And when there are resentments, when there are petty jealousies, when there are those things that are contradictory to Happiness and joy that are a part of the activity, these build those things that hinder those who would know the peace and the joy and the Happiness of just being kind, just doing that which brings to the experience of others that of joy, peace, Happiness to all. (262-110)