Add usable space to your yard. Here a troublesome slope was turned into a deck. The deck was carved into the hillside and surrounded by a retaining wall. Same principle to build nice size pool with deck area.
Make Storage Multitask (pool area?) Solve two outdoor problems -- a lack of seating and of storage -- at once. Transform wooden chests with paint and custom cushions made of waterproof foam and fabric. (For backyard toys, gardening stuff, and pool chems)