How does a skydiver reach terminal velocity?

At the start of the jump, the skydiver starts accelerating downwards due to his weight (force of gravity). There is a resultant force downwards as the weight is larger than the air resistance (weight>air resistance). As the skydiver accelerates and increases her speed, the air resistance on the skydiver increases. At terminal velocity, the air resistance has become so large that it equals the weight of the skydiver (weight=air resistance). This is because there is no resultant force on the skydiver - the weight and air resistance cancel each other out, therefore, the skydiver is no longer accelerating. This means that it has reached terminal velocity and is not increasing/decreasing her speed anymore.