Narrative Structure

Mainstream trailers will generally conform to the three act structure to get narrative across to the audience most effectively.

V For Vendetta
Act 1 (0:00-1:30)
The first act of this trailer is unusually long due to the need for a greater amount of time to establish the premise and setting of dystopian, totalitarian London and the character of V (as well as the more conventional Natalie Portman and John Hurt characters)
Act 2 (1:30-1:46)
Act 2 of the trailer is extremely short, which results in not a huge amount of the films plot being put across. The trailer focuses primarily on setting and character and the small amount of plot we get is either from these aspects or the short second act in which the development of Portman's character and the sinister actions of the government are depicted.
Act 3 (1:46-2:30)
This fairly long montage sequence depicts the high budget and large amount of action in the film, as well as accentuating its graphic novel roots. The soundtrack steadily picks up in pace, matched by the editing, and sound bites of particularly dramatic lines. All of this leads to the large explosions, falling dominoes, and flaming titles of the film, in true action thriller style.

Welcome To The Punch
Act 1 (0:00-0:20)
The basic crime thriller premise is established, as well as the McAvoy and Strong characters and their feud. The style and drama of the film is also established in these first 20 seconds.
Act 2 (0:20-1:07)
The narrative is expanded as Strong's son is wounded and he returns to London. The use of narrative in both Act 1 and 2 allows a fairly complicated story to come across fully in a shorter space of time. The soundtrack in Act 2 also begins to ramp up to Act 3.
Act 3 (1:07-1:50)
The montage even further relays the narrative using soundbites and images, whilst the explosions and gunfire solidify the genre of the film and create a more exciting montage and overall trailer. The convention of a crescendo at the titlecard is adhered to in the third act of the Welcome To The Punch trailer.

Only God Forgives
Act 1 (0:00-0:35)
Gosling's character is established in motives and narrative, as well as the policeman antagonist and Kristen Scott Thomas. The narrative is outlined as a revenge story and the premise, setting and style are established.
Act 2 (0:35-1:00)
A shorter second act takes place, as the key points of the narrative have already been established in Act 1. The antagonist is further fleshed out as a prominent danger and psychopathically violent man. The vibrant style of the trailer is continued.
Act 3 (1:00-1:59)
The longest montage of these three examples, this combines action and excitement with tension and drama. This can be in part attributed to the slower editing and soundtrack, making it a more paced trailer. Despite this, it can still be considered a solidly crime thriller third act, conforming to all necessary conventions.