when Jack wants rose to dance with him in the 3rd class party his hair is messy. Then when he grabs her hand it is slicked back and then messy again when they are standing together.

Oh yeah the one where Jack hands her the note and its yellow but when she reads it its white

When Rose is running in the hallways trying to find help for Jack when he is hand-cuffed, she finds a man and asks him to help her free Jack. She gets frustrated with him and says "listen" then hits him. In shots before (you can put it in slow motion to see it) you can look at the man's hand and it already has blood on it before he touches his face.

The Shooting Star - That one happens to be my favorite.
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in the nude scene rose had no hair under her armpits women in 1912 did not shave their under arm hair