Macbeth help!!Watch this thread
Key scene for guilt: Claudius prayer for forgiveness with Hamlet in background, debating whether he should kill him now or later. Claudius seems like he's not truly sorry, but at least he attempts to ask for forgiveness, which casts doubt over Macbeth's mind as if he kills the King now, he may go to Heaven as he'll die in a state of holiness (where he would MUCH rather him be subjected to the wrath of Hellfire)
It can be quite complicated so you don't have to understand everything in there, but if you're aiming for an A* it's a good way to get a feel of alternative interpretations etc.