There is of course a lot of imagery that is used in this play to describe the character of Macbeth. In particular, you might want to think about the various soliloquies he has and the kind of imagery that Shakespeare uses to help describe Macbeth, his feelings, and his situation. For example, in Act I scene 7, Macbeth uses the following imagery to describe his situation as he contemplates whether it is worth killing Duncan or not:
I have no spur
To prick the sides of my intent, but only
Vaulting ambition, which o'erleaps itself
And falls on th'other--
The image here is of a man who jumps so high when mounting a horse that he actually doesn't land on the horse, but flies straight over and lands on the ground. Macbeth here suspects his "vaulting ambition," and begins to understand that being obedient to his ambition might not actually be the best thing he can do.
In the same way, one of the most moving and desperate images associated with Macbeth comes in Act V scene 5 when he hears of his wife's death and says:
Out, out, brief candle!
Life's but a walking shadow; a poor player,
That struts and frets his hour upon the stage,
And then is heard no more: it is a tale
Told by an idiot, full of sound and fury,
This is an incredibly moving speech as not only does it describe Macbeth's grief at his wife's death and also his sudden understanding of how temporary and meaningless power is, but also it communicates an incredibly desperate vision of life. These are just two of the images associated with the character of Macbeth, but there are plenty more to discover in this play.
The flying dagger that Macbeth experiences could relate to the paranoia that he has and later is wife because of the guilt they feel in having participated in murdering King Duncan. That's just what i can think of right now. Sorry