One concept--an abstract or general idea inferred or apprehended from specific instances--that comes from the novel, Great Expectations is the absolute value of love. For, love transcends social class, love transcends generations, love transcends all else.
In the First Stage a young Pip recounts that he "looked up to Joe in my heart." However, he does not understand intellectually the value of this love until he becomes a young gentleman and rejects Joe's love only to discover that his false values are of no worth. For, Estella and Miss Havisham, whom he has held in high regard cause him agony.
Finally, as in the Bible, what Harold Bloom calls the greatest literary work of all time, specifically St. Paul's letter to the Corinthians, Pip sees in "a mirror dimly" that he has been selfish and cruel to those who love him: Joe, Biddy, and Magwitch. Pip gives up his selfish, childish ways and sees clearly that above all else, love is the greatest of values. To paraphrase St. Paul, Pip now fully understands that faith, hope, and love abide; but the greatest of these is love. He tends lovingly to the poor, dying Magwitch; he returns to Miss Havisham and forgives her, even saves her from the fire; he forgives Estella; he embraces Joe, begging his and Biddy's forgiveness of his cruelty; and he performs an act of great charity and love towards Herbert.
Love is the concept, the ideal, that prevails throughout Great Expectations; it is nobler than any other concept--ambition, social class, etc.
Some concepts worth considering are these:
Drive, ambition, motivation: Pip is willing to lose his whole family to become more than he was. Likewise, Miss Havisham tries to get Estella to despise all men like she does and ends up destroying the person Estella could have been.
Class structure: Pip feels so much better than his family once he moves to London. He loses his friendship to Joe for a time because of this. Miss Havisham significantly makes class structure seem important to Pip.
Guilt and innocence: Miss Havisham feels significant guilt about what she does to Estella, but only just before she dies: "What have I done?" she confesses.
Truth and lies: The secrets that are kept from individuals about their families are too significant to miss in this piece. Read the attached piece of enotes site for more ideas.