1. An Inspector Calls
..dramatic effect :)
Kirstie, Toni and Rochelle.

2. Setting and Subtle Hints..
Setting and lighting are very important throughout the play to create tension and give the impression of a comfortable house.
The lighting reflects the mood of the play.
There are subtle hints that make the house not all that it seems such as Eric seeming awfully nervous about something.

3. Dramatic Irony..
There is dramatic irony in the play. For instance, the audience knows how wrong Mr Birling is when making confident predictions about there not being a war and his excitement about the sailing of the Titanic.
This puts the audience at an advantage over the characters and makes us more involved.

4. Tension..
There is a lot of tension throughout the play because every character is involved in the death of Eva Smith.
The audience is interested in how each character reacts to the revelations.

5. Timing.. Timing of entrances and exits is crucial.
For example, the Inspector arrives immediately after Mr Birling has told Gerald about his impending knighthood and about how "a man has to look after himself and his own."

6. Inspector Goole..
He controls the pace and tension by dealing with one line of enquiry at a time.
He is very mysterious and seems to know what is going to happen before it does.

7. The ending.. The ending leaves the audience on a cliff-hanger.
In Act 3 the Birlings believed themselves to be off the hook but then discovered that the Inspector wasn't real and that no girl had died in the infirmary.
Some of the tension is released - but the final telephone call, announcing that a real inspector is on his way to ask questions about the suicide of a young girl, suddenly restores the tension very dramatically.
It is an unexpected final twist.