To evenly space miniature ceramic tiles, apply a heavy coating of rubber cement on a piece of poster board that can later be glued in position on a dollhouse or project wall. This allows you to lay the tiles on a flat surface instead of trying to work them on an upright wall. The rubber cement holds the tiles in place but still allows them to be repositioned.
Use two or more straight-edged razor blades to create equal grout gaps. Vertically line up the first column of tiles and press flush against one up-right blade (fig 1), then separate them horizontally with a second blade (fig 2).
For the second column of tiles, hold the first blade in position and repeat the process on its other side (fig 3 & 4).
As you work across the area to be covered, you can repeatedly check and correct the tile placement by inserting blade edges to maintain gap uniformity (fig 5).
Once you are satisfied with the tile layout, use a scrap of wood or other stiff scrap to apply even pressure on the tiles so they are all uniformly flat. Check to make sure none of them have moved out of position and press again if necessary. Use lightweight vinyl spackling compound for grout. Press it into the grout lines with your fingertips and let it dry. Then, use a damp paper towel to wipe away any excess.