Little quilts made from past clothing can be displayed. Anything handcrafted is wonderful. Avoid the library look . Stack books in groups both standing up and laying down. Add decorative elements between the stacks of books to soften the look.
Plants are great, as well as anything black, or a shiny metallic color.
Don't fret about the occasional misplaced hole in the wall. Keep the spackle and paint handy for when you are done. If you are very insecure about where to put things, try putting masking tape on the wall around the border of the object you want to place there and see how it looks. You can also use large pieces of paper to get a feel for relationships of items next to one another. You can also do it on the floor first.