Needle and sowing thread
piece of denim in the size of the jackets back (get it?) and how long you want it. I used another denim jackets sleeve and made that one into a vest.
First start by cutting the piece of denim to the wanted size (take a little more just in case).
Then sow the denim on where the jacket originally got sowed together.
Cut the denim you just sewed on. Start by cutting the denim half up in pieces that are 1/2 inch wide. Does this make sense?
Rip the half cut pieces up to the top, but not all the way or it will get ruined.
There you go! You just got a Lana Del Ray inspired denim jacket!