There is a couple of ways of doing that. You can pull the fork tubes up in the triple clamps and make sure the shock spring preload is set at the lowest setting. An another alternative is to replace the stock rear shocks with some shorter ones. I have also seen people remove some of the seat padding to accomplish this. Lowering the motorcycle will impact the handling and ground clearance, usually in a negative fashion. Out here on the left coast I have seen vertically challenged officers double sole their boots also.