The following are some scenes i can describe from the Trailer:

# Death Eater talking to Voldemort
# Harry Potter walking alone at the Forbidden Forest and face Voldemort.
# Harry, Griphook & Hermione (disguised as Bellatrix) riding at the gringotts cart. [Ron at the back of Harry and a big guy at the back of Griphook]
# Ollivander
# Hagrid & Harry riding at Sirius' motorbike
# Ron & Hermione outside the Shell Cottage
# Hermione walking alone at a Muggle street
# Harry lying down in a forest
# Hogwarts covered with globe like fire..
# A Death Eater blocking the Hogwarts Express
# Gregorovitch
# Hermione preparing for some spell, Harry with Ron (lying on the ground) at the background
# Gringotts' Dragon wanted to escape
# Voldemort and his followers
# Ron & Hermione at the battle
# Bellatrix Lestrange throwing her dagger
# Filch at a corridor (with some burst on the background)
# The trio at the Forest running from the Snatchers
# Harry & Voldemort confrontation
# Dragon escaped from Gringotts
# Battle at the Ministry of Magic
# Nagini attacks Harry Potter at Bathilda's house
# Neville kills Nagini
# Room of Requirement with Fiendfyre
# The Trio trying to escape the Fire
# Ginny kiss Harry
# Snape at the Headmaster's Office
# Harry battling at the Cafe
# Explosions at Hogwarts Grounds
# Finale: Harry & Voldemort duel



- Sadly, some characters like Draco Malfoy, Luna Lovegood and Weasley Twins are not featured on this Trailer