To create a retaining wall all you need to do is follow these simple steps. To begin you will need to get many interlocking wall blocks and either sand or concrete. The first step is to plot and measure the retaining wall's size and shape. Use your measurements to figure out the amount of retaining wall blocks that you will need. The second step is to mark off the spots in your yard that you would like the retaining wall to be. Then dig your trenches in these spots to level out the land and then put patio paver base in the trenches to further level out the land. Compact the gravel with a tamper. Make sure the ground is still level then start laying the bricks. If your wall is two feet or higher then you will need to install drainage pipes to drain excess water. Add topsoil to your retaining wall then finally add flowers to finish it off.