Most car rental agencies in major airports will give you a "rules of the road" summary.

As long as you know how to negotiate roundabouts you will have few difficulties.

Bear in mind, most rentals are manual transmission. For my part, I prefer it, but if you have only driven automatics, you will have the twin problems of remembering that you are driving a manual transmission--and the orientation. The gear shift and pedals are not mirror image, so you still use your left foot to clutch, but you push into 1st instead of pulling. It can be disorienting for a while.