Whether you’re tiling a floor or a countertop, first and foremost be sure to use thinset mortar that is latex- or polymer-fortified; otherwise, it is likely to crack, resulting in loose tiles. You can buy “polymer-fortified” thinset mortar that you mix with water, or you can buy less expensive, unfortified thinset and add liquid latex as directed.
Use gray thinset for ceramic and stone tiles that are dark in color. However, many types of marble, glass, and other kinds of tiles are slightly translucent, so a gray mortar would slightly muddy them. For these tiles, use white thinset, which costs only a bit moreFor most tile installations, a square-notched trowel with 1/4 inch notches produces grooves of the right thickness. For thicker tiles,while you work-either on the surface or in the bucket-discard it and mix a new batch.