Use Ikea Knuff magazine files as under sink storage holders. Screw a magazine file holder to the inside of kitchen cupboards. Add space to store more bulky items like chopping boards, cleaning products etc.
a hinged full length mirror from IKEA (Stave mirror - that is x hides jewelry storage -- brilliant idea from The Girl on the Go! I would use a thin sheet of plywood cut to fit behind the mirror so I don't put so many holes in the wall.