By the end of Act One, Macbeth is so stressed out and anxious about his decision to kill the king that he actually hallucinates. On his way to commit the murder, he sees a dagger, first clean and then bloodied, floating ahead of him, as if pointing him toward Duncan with the very same kind of weapon he will use to do the deed. Also by the end of Act One, we have seen how manipulative Lady Macbeth is and how easily she seems to be able to control her husband. Her insults regarding his cowardice and incapability will come back to haunt her later. His desire to become king compels him to move forward with the murder, even when his own brain seems to fight him, and his wife's awareness of his desire makes it easier for her to manipulate him.

By the end of Act Two, Macbeth has killed Duncan's two chamberlains, the men he and his wife were attempting to frame for the murder. This was not part of their plan, and may indicate Macbeth's desire to tie up loose ends on his way to the throne. He wants to be king and so he cannot get caught for his crime. Further, we see the unnatural events that seem to be taking place as a result of Macbeth's crime against nature, killing Duncan: it is pitch-black at midday (as though a light has gone out in the kingdom), a small owl (associated with witchcraft) has killed a falcon (associated with royalty), and Duncan's horses tried to eat each other (as his former friends and family seem to have turned on and suspect one another). Without his desire to become king, he would not have committed the unnatural crime that led to these unnatural events.

By the end of Act Three, Macbeth has hired murderers to kill Banquo and Fleance because of the Weird Sisters' prophecy that Banquo would "father kings." Macbeth does not want to give up his crown to benefit Banquo's issue because he did so much in order to secure it for himself. He wants to keep his power. We also see that Lady Macbeth isn't happy or satisfied either. They fought so hard to become king and queen, but now she feels they have gotten "[their] desire . . . without content." They only possess a "doubtful joy," possibly because of the path they took to the throne. If he hadn't have desired to become king, the pair might still be happy back in their original station.

By the end of Act Four, Macbeth has become responsible for the murders of Macduff's wife and children. He feels that, now, "the very firstlings of [his] heart shall be / The firstlings of [his] hand." The best way, he thinks, to hold on to his power is to not stop and consider his actions before he takes them. Moreover, Macduff succeeds in convincing Malcolm that now is the time to return to Scotland from England in order to put a stop to Macbeth's tyranny.

By the end of Act Five, Macbeth's own men are turning on him and joining the other side to fight against him. His desire to become king and, later, to keep his power, caused him to do dastardly things that have alienated his subjects. He has also realized that his desire to become king and the actions he took to do so have led him to a place in life where he lacks real friends and no one respects or loves him.

The following are some suggestions. You can find a thorough discussion of this play in the eNotes study guide and other materials.

Act One

Macbeth begins thinking about murdering King Duncan because of what the witches told him about becoming king.

Macbeth discusses murdering the King with Lady Macbeth, who encourages him to do so that very night.

Act Two

Macbeth tries to get Banquo to join in his plot against Duncan.

Macbeth actually murders Duncan.

Act Three

Macbeth has Banquo murdered because he is afraid of him--especially since the witches have prophesied that Banquo's heirs will be kings. He thinks Banquo knows he killed Duncan and might inform on him. He suspects that Banquo might kill him in order to make sure his sons would become kings.

Duncan's son Malcolm has fled to England and  is raising an army to invade Scotland and unseat Macbeth.

 Act Four

Scotland is in chaos because of Macbeth's incompetent and despotic rule. See opening of Scene 3.

Macbeth has Macduff's wife and children murdered to punish Macduff for deserting him and to set an example to discourage further desertions.

Act Five

Lady Macbeth, who helped her husband kill Duncan, seems to be losing her mind due to guilt. She dies, probably a suicide.

The English army reinforced with Scottish deserters overthrow Macbeth's weakened army.

Macbeth is killed by Macduff.