If one big wall won't do, several low walls with level terraces between may be the right solution. Consider paving a level to create a patio and a comfy seating area. An inviting midslope patio is a great place to sit and survey the rest of your garden.
Great success with planting a slope has to do with the types of plants you use. Here are some great tips, ideas and photos. For low maintenance, be sure to use drought tolerant plants! (Patio Step To Lawn)