The beginning: Harry Starts off at the Weasleys' not on Privette Drive
Because Harry was at the Weasleys' house they skipped the whole part with the Weasleys coming by flu network and the whole candy incident
They skip out Ludo Bagman COMPLETELY! So the twins never lose their money to him and then need to get the gold from Harry later after he wins the Triwizard tournament in order to make their joke shop
At the World Cup they skip the whole part of Hermione helping Mr. Weasley trying to light a fire,of them going to get the water and all the interaction that goes on there
They skipped the whole World Cup game
They skipped the whole veela part, so you never find out that Fleur could be related to one because you never find out what they are
They made the dream that Harry has a reoccuring dream
They added Barty Crouch Jr. into the dream
They made Harry fall in the camp and see Barty Crouch Jr. put up the Dark Mark when in the book it was Crouch, but he was under the invisibility cloak and Winky the house-elf was blamed because she was supposed to be watching him
They skipped out Winky completely
They went straight from the train into the arrival of the schools for the tournament, which in the book didn't happen until christmas
It was supposed to be night time when the schools came
The school was supposed to be waiting outside
When Durmstrang came, the whole lake was supposed to turn into a whirlpool before the ship came up, but the ship just popped up
Madame Maxime was supposed to be big-boned, but she was just really tall
Mad Eye Moody turns Malfoy into a ferret and bounces him around the great hall. He doesn't bounce him up and down outside in the courtyard
The piece of paper that is supposed to have Harry's name on it that flies in front of the camera is a blank piece of lined paper - they use parchment, not notebook paper!
They didn't show enough of Rita Skeeter
For the first task it's Dobby that gives Harry the Gillyweed when he wakes him up 10 minutes before the task
Ron doesn't find out about the task before Harry does
They never showed Charlie Weasley
They never showed the way the judges judge - the ribbons that come out of the wands and twist into the number
They skipped the whole scene with Hermione's teeth being enlarged and then shrunken before the Yule Ball
Hermione was supposed to wear her hair up in a bun not down
Ron was supposed to try and tear the lace off of his robes and make them worse than they already were. And he was also supposed to get them when they went to Diagon Alley, which they never did
Viktor Krum pronounced Hermione's name correctly
Hermione wore the wrong color dress
Hermione acted schizo - one second she was happy and in the next scene she was yelling at Ron that he ruined everything and yelled at Harry and told them to go to bed - something's missing there
The third task was the maze, but in the book they were supposed to encounter many different creatures, but in the movie it was them against the walls of the maze.
They never showed Care of Magical Creatures class - the Blast Ended Screwts
In the graveyard, I think Peter Pettigrew cuts off the wrong hand
Harry was supposed to be layed over a regular headstone, and yet he was restrained by a statue
Mad Eye Moody's office is supposed to be IN the school
Harry never recieved his gold at the end of the tournament
They didn't show how they captured Rita at the end of the movie
OTHERS - There were others but my brain is a bit foggy now, if you noticed any others, please comment and include them