Place a drop cloth over the floor immediately beneath the walls you will be painting.
Apply painter’s tape along adjacent surfaces that surround the walls — windows, doorways, baseboards, ceilings and any adjacent walls.
Pour the first paint color into the left half of a paint tray. Pour the second paint color into the right half of the tray. Allow the two colors to fill the tray side by side — they will eventually begin blending, which will help create an attractive effect on the wall.
Roll the paint roller in the paint colors in the tray to load it. The colors will coat each half of the roller, touching in the middle.
Apply the roller to the wall, rolling it in diagonal directions to the left and to the right. As you roll the paint roller, it will apply both colors to the wall at the same time. Rolling more will blend the colors more, and rolling less will keep the colors less blended.
Stand back to assess the wall after rolling paint onto it several times. Determine whether you like the colors blended more or less.
Continue loading the paint roller with paint and applying it with the roller, blending the paint colors as much or as little as you prefer. Paint each wall with the two colors of paint until you finish.
Load a flat paintbrush with both paint colors, and pounce the bristles in an up-and-down motion along the outer perimeter of the walls to cover the areas where the paint roller could not reach. Blend the perimeter paint seamlessly with the other paint around the entire perimeter of the walls.
Remove the painter’s tape.