Rule of the Game

Decide on some basic rules. Smoking, eating, loud music, radio station, talking in the car – all these are details which, if sorted out in advance, will make your carpooling enjoyable.
 

Waiting Time

Decide on a waiting time and how many calls you are going to make. 5 - 10 minutes and 2 calls are usually a good starting point.
 

Cost Sharing

One of the benefits of carpooling is that you can share the costs of gas, maintenance, parking, etc with your potential carpooler. If you both agree to share such costs, it is advisable to discuss the issue before actually carpooling in order to avoid any confusions later.
 

Backup Strategy

Have a backup plan in case the driver falls sick, goes on vacation or the car breaks down.
 

More Etiquette

Simple strategies like big and tall in the front can make the ride pleasant for all. If you are driving, tidy up your car. Don't do errands on your way without consulting others - it is usually best to carpool straight to and from the destination.