Ms. Miller has longer hair during "For the Last Time, I'm Dominican". This is because this was filmed after Judy Reyes (Carla) recovered from her pelvis infraction and was able to tango with Donald Faison (Turk).
At the beginning of the song "Guy Love", Turk has the clipboard up to his check, and then it jumps to the next shot and the clipboard is at his waist; the clipboard's still at his waist, but when Turk sings, "...some times it's easier to hide..." another shot is ran and the clipboard has suddenly disappeared from the shot, and we can only assume it's at his side with his arm. The clipboard has suddenly disappeared (or at Turk's side, out of shot) whenever the camera does a mid-shot and over-the-shoulder and focuses on JD, but reappears whenever it's focused on Turk.
Dorian's key is in his chest pocket before Elliot gives it to him.
In the second scene we see Dr. Kelso in the beginning, his name tag changes positions.
In the opening scene, when Carla is sat at the table, working out her finances. As she says "maybe I should stay home with Izzy for a year". It cuts to Carla sat holding a pen up by her face. Then when it cuts to the wide shot her hands are under the table. Then when it cuts back to the close up, she is holding the pen in both hands by her mouth.
In this episode, Elliot tells J.D. that she's 29. After college, 4 years of medical school, and 5 1/2 years at Sacred Heart, she should be at least 30, even assuming that she entered college at age 17. This could also be a reference to the Season 4 episode "Her Story" where all of the women in the hospital stated their ages were 29.