The opening credits of the trialer is the WarnerBrothers logo depicted as an overhead view of a city, confined by the outer rim of the logo; perhaps suggesting the city within the confines of the human mind.
This spinning top on a water-stained surface, marks the first of many times that water appears in the trailer. This could be considered significant as the film's site is a replica of this shot, but could just be a red herring.
An overhead shot of the city possibly just an establishing or point-of-view shot, but important because only one building has a readable sign here, that being "MITSUI GARDEN HOTEL" on the upper left. This could be the hotel hallway that is later seen within the trailer.
This shot of Leonardo Dicaprio looking through a rainstreaked window shows leo looking on with apprehension at something going on outside his vehicle. There is at least one other person there with him, and an "EXIT" sign is visible in the background. And look there's the water again. My guess is that this shot is connected to the next shot due to its sense of continuity.
Point-of-view shot through rainstreaked window, possibly the view is of a helipad with two men dragging a man away from what seems to be a helicopter window. Upon close inspection, he has a bloody lower lip. Perhaps a fight breaks out just before? Maybe he's pursuing Leo, if the previous shot is connected, thereby explaining Leo's apprehension.
A glass of water on a wooden table significant, if only for the fact that the table and glass stay completely still, yet the water inside is tilting to one side as though the water and the other objects in the scene lay on different planes of gravity. I believe this to be indicative of the perspective-altering properties of the film.
This text "YOUR MIND" appears centered in the screen, between buildings and quickly rotates along with the cityscape as though it were a building. This may be yet another conveyance of the properties of the world of Inception.
Leo notices something behind him and judging from the skyline behind him, he seems to be on a roof, as there is no glass obscuring the city behind him. Also, not much surprise is registering with him, so whatever he's seeing can't be too astounding. A minor revelation here, at best. Perhaps the least telling shot. This shots best purpose is to get a better looks at the actors face.
The text "IS THE SCENE OF THE CRIME" continues on from the text "YOUR MIND", the buildings actually seem to be moving, again reiforcing the idea of inception.
This fight within the hallway is the meat of the trailer and by far the most likely piece to grab the attention of the consumer. Here, two actors/characters run at each other from opposite ends of the hallway. At the left side of shot 10, you can make out the room number 491, possibly placing the location of teh shot withing the hotel shown before.
Someone bursts out of the bath, the most significant looking water shot. Being suberged in a bath is not usually pleasent and watching closely, you can see that water is escaping the man's mouth. Maybe he was being drowned, but there is noone elses hands.
This extreme close-up shot of a clock seems to be recreating the current perspective of the world as all of the events shown so far are happening in a matter of seconds.
Leo waking up or being startled - too little context to guess much about this. He starts with his eyes closed so either he is waking or just being shocked by something. All the same, we see light flash just outside to the left of him so he is likely to be sitting next to a window.
The titles are finally revealed by starting off as a skyline shot of a city before becoming the "Inception" logo. saving the film name till the end of the trailer first grabbed the audiences attention the kept them in suspension.