How to properly learn a difficult piano song?

Well always start by using the hand your most comfortable with practicing with that one first (as this person said some what down below, switch hands)

Try not to feel pressure because sometimes when your stressed or feeling down or are nervous you dont pay close attention.

Sometimes it is good to hear the piano piece on yt, and listen to other play it, it will bring up your confidene and you will most likely, if learned, play along to video.

Think positive. People may say you cannot do things sometimes but never give up keep practicing, even if you miss a note or two. If you practice at least twice a day it could help you remember the notes.

Make sure to read notes and the lyrics if it has any, it is good to know what your playing especially reading and singing along, if anything it would help with vocal if you arent a singer.

Repeat all of this until you are comfortable and are sure you can do the piece. But remember sometimes you should practice and not look at the sheet of the music, as a game of memory, to test to see what you can and cant remember to play, it helps.

Stay confident and all of these above will help you :)

all of them except "c"