What were 3 tragic flaws that lead to Macbeth's ultimate downfall in Shakespeare's Macbeth?

In Shakespeare's Macbeth, the tragic
figure, Macbeth, is considered to have one tragic flaw, ambition.  And one tragic flaw
is the norm for a tragedy.  One wouldn't expect more than one tragic
flaw.

The witches predict that Macbeth will be king, but he
is so ambitious that he takes that idea and turns it into I will be king
now!  And the only way he can make that happen is by assassinating
Duncan. 

Then, once Duncan is dead and Macbeth is king,
that's no longer enough.  At that point, being king himself is not good enough--he wants
his heirs to be kings as well.  He wants to create a dynasty.  This leads to the rest of
the killings, which cast suspicion upon him. 

His ambition
leads to the destruction of Duncan, Banquo, and Macduff's family, and ultimately to his
own destruction.

Just as a sidenote, if you need a couple
of major mistakes Macbeth makes in order to come up with three parts for your answer,
you could use Macbeth's killing of the grooms, which was not part of the plan.  This
raises suspicion, at least in Macduff's mind, that Macbeth is guilty of treachery.  A
second mistake that he makes occurs when he shuts Lady Macbeth out of the
decision-making process:  she is the planner of the family.  When he starts making
decisions for himself, he really starts making mistakes (the rest of the killings, and
the failure to kill Fleance).