I would make a potion that could make you see people's memories kinda like a pensive but your actually there like in COS kinda lame ano but I may need more time to think about poo it it more properly

BIPPITY BOPPITY BOO. XD

i would make a spell that shows the feelings two people (witch and wizard or witch and witch or wizard and wizard) have for eachother by touching the tip of thier wands together by showing different coloured smoke for each feeling
Grey: feels nothing
Blue:Friends
Pale pink: like eachother
Pink: family
Dark Pink: true love, will always be together/in a romantic relationship
(Note-I have used this in my fan fiction about harry and Ginny after the war)