It's made abundantly clear that the Kellys live in Michigan, yet Jules' Harvard admissions letter is addressed to her at an address in Granger, Indiana.
The number on the Kellys' house is 51584 (clearly seen in a daytime shot), yet Jules' Harvard admissions letter is addressed to her at 14 Bittersweet Road.
Jules tells Alex that her Harvard interview is on Friday, yet earlier in the movie we see the calendar page for November 2015, where the 30th is clearly on a Monday.
The Cambridge Daily newspaper that has Madison's picture on it is dated Thursday November 11, 2015. That date was actually on a Wednesday.
It is quite obvious that Jules is wearing glasses that don't have lenses in them. It's most obvious in all shots showing her from the side, such as when she is ordering ice cream from the vendor at the carnival at the beginning of the movie.
(at 28 minutes) The bad guys are fiddling with the video game as if they're playing it, yet when Victoria goes to turn the TV off, the screen clearly says "Pause Menu" in big white letters.
All newspapers shown have fake dummy text instead of real words for the articles.
Once they go inside the pawn shop, you see through the windows that there's no truck stop diagonally across the street. It's all bunch of trees and forest area on the side of the road.
The Negative Ions' concert is on November 29th, as shown on a few posters. The beauty pageant and the Harvard interview are both on November 30th. However, the events in the movie play out as if there is an extra day in between the concert and the pageant/interview.
The Cambridge Daily newspaper that has Madison's picture on it is dated Thursday November 11, 2015. At this point in the movie, it is either the 29th or the 30th. It's highly unlikely that someone would be reading a nearly three week old newspaper.