My experience with urology has been more oriented towards an academic center. The docs there are typically in the OR 3 1/2 days a week. Three of those will be the larger cases - onc type. Then, they often spend 1/2 day doing cystoscopic procedures. One day of week is clinic seeing new patients in the morning and then follow up patients in the afternoon.
The best way to obtain a urology rotation is pretty much the same for any other surgical subspecialty.
1) Get step I scores - >230 is important, but I know of people who have matched in the 220's.
2) Get as many honors as possible in the 3rd year. Surgery and medicine are key rotations to honor.
3) Take 2-3 electives in urology - get honors in each one of them.
4) Get good recommendations from urologists/chairmen where you did these electives.
5) Apply to a large number of programs to increase your odds.
6) Research never hurts to do in urology.