When you have collected or purchased your rocks, plants, and soil for filling around the plants, you are ready to begin. Whether creating a wall or a small garden, start at the lowest point and work toward the highest area. If you are contouring the landscape, save the soil you remove in one location to add height to another area. When constructing a rock wall make sure the wall is slanted back toward the slope one inch horizontally for each vertical foot of wall. Tilt the flat surfaces back toward the slope to catch the water.
All rocks have a better face and a more stable side.
With luck, the most stable placement of your rocks will showcase the more interesting face. Try to bury at least half of each rock in the soil so it will be firmly anchored and have a more natural appearance, not just sitting atop the ground. Water the plants and soak the soil around the rocks thoroughly to settle and compact the soil. Any soil added as fill should be wet. Slugs and some insect pests may find the cover of rocks to be the perfect hiding place.