What was the result of Abigail's evil plan by the end of The Crucible and what did she gain?
Abigail's plan seems to evolve over the course of the play. At first she is simply attempting to save herself from being hung for practicing witchcraft in the woods with the other girls. Later she attempts to win back John Proctor by accusing Elizabeth Proctor.
In Abigail's first and, arguably, most important goal, she is successful. As the play opens, Abigail is in a very bad position. She lives with an uncle who she cannot trust to defend her. (If Parris feels that his position in Salem is threatened by his association with Abigail, he may cut ties with her. This is implied in their discussion in the opening scene.)
She is likely to be accused of witchcraft because she and her friends have been caught dancing naked in the woods. Abigail has been seen drinking blood. The punishment for such an act is death.
Knowing that she has to do something to protect herself (and her uncle, Reverend Parris) if she is to maintain her place in Salem, Abigail thinks quickly and begins to deflect attention from herself and her friends. By accusing others of witchcraft, Abigail is able to save herself. Eventually, she flees the town.
Parris informs the investigators that Abigail has taken money from his safe and left town.
Alive in the end, we can say Abigail's primary plan is successful.
The second plan Abigail carries out is not entirely successful. Abigail wants to regain the affections of John Proctor. To do this, she accuses Elizabeth Proctor of witchcraft. Elizabeth is convicted and sentenced to death, but John Proctor will not take Abigail back. He looks at her as an enemy.
When Abigail refuses to recant her accusations against Elizabeth at court, Proctor lashes out at her.
Proctor, in his anger and desperation, grabs Abby and calls her a whore.
Abigail's second plan succeeds in "getting rid of" Elizabeth, but fails to help her win back Proctor's affections.