Pay attention to the car behind you, and maintain an equal distance between it and the car ahead. With a buffer, if the driver in front briefly brakes, you won't pass the hiccup along.
Drive at the same speed as the cars around you. Accelerating to catch up to the vehicle ahead will result in braking or switching lanes, which may force another driver to slow suddenly.
Buy a car with an adaptive cruise-control system to automatically sync your speed with surrounding traffic. Or, save up for when a self-driving car hits the market.