A book safe is such a fun project and adds a whole other level of cool to your bookcase. Keep all your trinkets and valuables out, in plain sight without anyone knowing they are there! DIY instruction (Cool Rooms In Houses)
Upcycle plastic containers (spray / detergent bottles) into baskets, gift bags, containers, etc. Maybe larger square gallon jugs for holding craft supplies or keeping small things together in the closet, or.