Some Cayce quotes to get you started:
... if ye become interested in others, others are interested in you! (3541-1)
Keep it [your soul] then in patience, in love, in gentleness, in kindness . . . For these are indeed the fruits of the spirit . . . And remember, a kindness sometimes consists in denying as well as granting those activities in associations with thy fellow man. (5322-1)
For as is indicated in the law that changes not, the manner in which ye treat thy fellowman, ye are treating thy Maker. Thus each individual soul-entity meets its ownself and must give an account for the deeds done in the body and in the body-mind. For that ye thinketh in thy heart, so are ye. (5082-1)
. . . justifying of self is blaming someone else. (2803-2)
Unless those activities among men are the aid for the greater number, rather than for the class or the few, they must eventually fail. (826-2)
... those that find fault with others will find fault in themselves; for they are writing their own record – they must meet, every one, that which they have said about another; for so is the image, the soul of the Creator in each body, and when ye speak evil of or unkindly to thy brother, thou hast done it unto thy God. (487-17)
There must be first the quiet or harmony in one's own self if one would find harmony with the association with others. (1540-7)
... unless each soul entity . . . makes the world better, that corner or place of the world a little better, a little bit more hopeful, a little bit more patient, showing a little more of brotherly love, a little more of kindness, a little more of longsuffering – by the very words and deeds of the entity, the life is a failure; especially so far as growth is concerned. Though you gain the whole world, how little ye must think of thyself if ye lose the purpose for which the soul entered this particular sojourn! (3420-1)
Learn the lesson well of the spiritual truth: Criticize not unless ye wish to be criticized. For, with what measure ye mete it is measured to thee again. It may not be in the same way, but ye cannot even think bad of another without it affecting thee in a manner of a destructive nature. Think well of others, and if ye cannot speak well of them don't speak! but don't think it either! (2936-2)
Faults in others are first reflected in self. When such conditions arise in the experience of an entity, there should be first those considerations of that in self that has produced such a reflection, so that the God shining through any activity is lost sight of by self in the fellow man; especially one that is seeking for the spiritual activities in a material plane, and he that would gain the world and lose self's own soul has lost all. (452-3)
For there is only the one ideal in HUMAN relationships, and that is as that given by Him who IS the way, the truth, the light: "Love thy neighbor as thyself." (1598-1)
Try to see self in the other's place. And this will bring the basic spiritual forces that must be the prompting influence in the experience of each soul, if it would grow in grace, in knowledge, in understanding; not only of its relationship to God, its relationship to its fellow man, but its relationship in the home and in the social life. (2936-2)
As ye mete to others, it comes back to thee. As ye would that others should do to thee, do ye even so to them. (1688-9)
Friendships are only the renewing of former purposes, ideals. (2946-2)
Know in self that the greater part is ever within self when trouble arises between self and daughter, between self and neighbor, between self and husband. For that we think, that we give voice to in condemnation of others, we will find within our own selves. For the Lord thy God is one. And where ye condemn, so are you condemned. As ye forgive, so are ye forgiven. (3457-1)
For if thou seest not in thine enemy that thou would worship In thine God, then thou hast not caught the light. For GOOD alone may wholly, materially manifest in an earthly world; for so came thy Lord into flesh. EVIL only hath its appearance in the mind, in the shadows, in the fears of those that know not the light in its entirety. (689-1)
... let that purpose be in thee which is the basis of ALL human relationships for the better, the greater spiritual understanding, to wit: "As ye would that others should do to thee, do ye even so to them." (1158-15)
Keep the mental attitudes of helpfulness and hopefulness in its relationships, in its dealings with the fellow man. For these will make for greater returns in harmony and peace within self, than may be acquired in any other way or manner. And also bring for SELF, not only a useful life but useful in a PURPOSEFUL manner. (1100-6)
For, the experience or sojourn in the earth is not by chance, but the natural spiritual and soul evolution of the entity; that it may be aware of its relationships to God--through its relationships to its fellow men; recognizing in each soul, as well as in self, those possibilities, those opportunities, those duties, those obligations that are a portion of each soul-entity's manifesting in a material plane. (2271-1)
. . . what are friends? That in which there may be the testing of our own abilities, as to that application of truth related to the divine and to mental reaction in relationship one to another. (2772-5)