When mixing the grout prior to application, follow the directions on the bag and only mix enough for about 30 minutes of work. It will dry out too much if you mix up too much at one time. Use a padded grout float to evenly spread the grout over the tiles and into the joints. Make sure that the grout in the joints is flush with the top of the tile. Work in sections, usually a 3-by-2-foot area.
Work in the same 3-by-2-foot sections with a damp sponge and wipe off the grout from the surface of the tile. Establish a routine: grout a few sections and then go back to the first section and start cleaning. This will allow an appropriate amount of time for the grout to harden sufficiently to avoid wiping away any grout from the joints. Rinse the sponge out between strokes and use both sides.
Working with mosaics and grout is similar in procedure to granite or ceramic tiles. Mix up a small amount of grout according to package directions. Rather than a grout float for applying the grout, use a squeegee or tiler's sponge, or your fingers. Press enough grout around the mosaic tiles to create a smooth surface. The grout in between tiles needs to be flush with the surface of the tile. Wipe off the excess grout, wait about a half hour and then use a wet towel to remove any grout from the surface of the tile.
Prior to grouting, ensure that the tiles are firmly in place. Joints to be grouted need to be free of dust and clean and dry. Do not mix different brands of grouting mixtures with each other. Apply a sealant coating to unglazed tiles or natural stones prior to grouting for easier clean up. Use clean tools that are free from debris of previous grouting projects.