I mounted an export company of marble and granite and would like to know the best way to attract customers to?

On a large scale, you would need to hire sales staff here in the states to talk to distributors or suppliers and try to sell to them at a lower rate. On a smaller scale, you would need to obtain a warehouse or distributing center here, and again hire sales people to sell to installers and craftsmen who actually use the masonry in building or remodeling.