Character
When attending a murder mystery, participants will have a character to play. According to a Dinner and a Murder, one piece of information that shouldn't be given away is your character's details. Only offer general information about your character.
Identifying the Weapon
A first objective in solving a murder mystery is discovering how the murder was committed. In some murder mysteries, it may be easy to identify the weapon.
Time Frame
Another aspect of murder mystery solving is figuring out when the murder could have been committed. Asking other participants for their alibis can lead to the possible murderer.
Motive
You can usually determine a guilty person by identifying the motive behind the murder. There may also be clues at your murder mystery such as objects that belonged to the deceased; which can help lead to the guilty person.