washi tape + polariods = "you are the one that i want for the rest of my dayssss" (if you know the song, u'll get it :P)
Washi tape picture frames make for a lovely, informal, and super-affordable take on the gallery wall. Image from Design*Sponge.
Deer--make with washi tape on the wall
bang bang: minor make-over of room corner
The colours on the wall
Flowers on the wall with washi tape