First off you're taking the course at a transition period. Much of the law of Criminal evidence is being altered by the Criminal Justice Act 2003- and most of it hasn't been ruled on by the courts yet. This is a problem because as with most legislation it is fairly vague and incomprehensible.
However my main advice would be to make sure you understand the purpose of each particular rule- i.e. why hearsay is unacceptable. This makes it easier to understand the various exceptions. i.e by realising that hearsay is unreliable because it cannot be cross-examined and there is no effective check and balance, makes it easier to understand why a dying declaration is allowed- because of a belief that someone on deaths door would be telling the truth.
Hope this helps- if not let me know!