Print or make a picture or plan of what you want your mosaic lighthouse to look like. If you are adding the mosaic to a sculpture, then a plan typically is not necessary unless you want a picture on the sculpture.
Separate the mosaic tiles by color. This will help you choose your colors more quickly and for best effect.
Create the lighthouse by placing the mosaic tiles on your surface after first applying a light coat of spray- or brush-on adhesive. The key to making the piece look like a mosaic is to leave a small amount of space between the tiles. Don't try to make all the pieces fit together.
Allow the adhesive to dry for at least four to 12 hours depending on the type that you use. You do not want the tiles to move around as you grout them.
Mix and apply the grout to the lighthouse, making sure that all grooves between the tiles are filled. Wipe off any grout that gets on the tiles. Allow the grout to dry completely before moving the mosaic.