Feminism would want to look particularly at the way in which there are such strong and dominant female characters in this play and the way in which they are shown to have power over men. For such a patriarchal period of history, this is key to focus on. There is of course the famous character of Lady Macbeth, who is shown to be stronger and more resolute (at least initially) than her husband. Note how she refers to her husband and her role in convincing him to take up the position that fate intended for him in Act I scene 5:
Hie thee hither,
That I may pour my spirits in thine ear;
And chastise with the valour of my tongue
All that impedes thee from the golden round,
Which fate and metaphysical aid doth seem
To have thee crown'd withal.
Lady Macbeth, at least in the first two acts of this play, is shown to be in control of her husband, and has the ability to chastise, cajole and bully him into doing what she wants him to do. She is a figure of female authority and dominance.
However, feminists would also have a lot to say about the witches in this play. They too exert power and dominance over the male characters, especially Macbeth. It is of course Macbeth who falls into their trap of listening to half truths and believing their words, and he is shown to be dumbstruck with amazement and fascination at their ability to give prophecies. The witches then would be another excellent example of female empowerment, as they show themselves to be ultimately more powerful than Macbeth himself by the way in which their prophecies play such a key factor in his downfall.