In the film when Jodi comes to see Travis on June 4 (the day/night of the murder) and tells him "that she just wanted to say goodbye", this would not have been accurate since Jodi had already moved back to California at that time.
In the film both Detective Flores and Prosecutor Martinez are depicted as having accents. Despite both being of Hispanic descent, neither has an accent in real life.
When Jodi is corresponding via text with Katie while Travis is in the shower, the time is 2:04 pm. Since the last photos of Travis alive and in the shower were at approximately 5:30 pm, this seems to be a quite obvious oversight.
Travis and Katie fall asleep on the couch. When they wake up the next morning, he finds on his mirror photos of them sleeping together. In 2008 it seems unlikely that Jodi would have had the ability to take those photos and have them printed immediately, in the middle of the night, and within a few hours, in order to place them there.
When Detective Flores is examining the photo of Travis' gunshot wound, he mentions that Travis was stabbed 27 times, but later in the trial, Prosecutor Martinez says that Travis was stabbed 29 times.
Jodi Arias is left-handed but the movie depicts her as right-handed.