The manners of leading and following in cars.
Leading, Not Leaving
These next few tips don't really need to be followed in order as much as they just need to be followed by the leader. The leader should maintain a safe and consistent speed. Keep up with the speed limit but consciously keep yourself from going too quickly. Remember that you know where you are going and can easily fall into your pattern and zip right off. Check your mirrors every few seconds to make sure you are leading and not leaving.
A consistent speed can help you with traffic lights as the other party should be fairly close. Don't rush up to an intersection. Be patient. That way should a light turn yellow, you will both either be able to stop easily or make it safely through the intersection without running the light. If the person following you is far enough back that he may possibly not make a light, slow a little when approaching the intersection in anticipation of the light changing.
The last little bit of this comes into play if none of the preparation pays off and the second driver is actually stopped by the light. Go ahead and find a safe place on the side of the road or in a parking lot to stop and wait for the other car.
Most routes are not very cut and dry. Many times there are multiple lane changes or someone just going slow and impeding your progress. Try to telegraph any turns or lane changes with your blinker. Turn that blinker on when you have barely even thought about making your move. That will help the other driver be able to plan his or her own move. Action taken at the last minute will usually put everyone in the second car in danger. The more lead time you can give-- the better. Just be sure to keep things minimal. Trying to zip around any car that might be in your way could send the wrong signals to the person following you. They could get in the wrong lane while trying to keep up, and completely miss an exit or a turn.