Pointing Object in the Direction it is going

Hi, Basically i have a game object “Hunter” witch fires another object “Dart” in 3 different directions, fires left ,straight and right and repeats endlessly, the problem i am having is to point that “Dart” in the direction it is going.

here is the sample i tried the LookAt and Quaternion.LookRotation with no success any help appreciated.

`while (canShoot)
start = _dartInstance.transform.position;

                _dartInstance.transform.position = Vector3.MoveTowards(start, destination, Speed * Time.deltaTime);
                //_dartInstance.transform.position = Vector3.Lerp(start, destination, Speed * Time.deltaTime);

                if (start == destination)
                    canShoot = false;
                    yield return null;
                yield return null;


Then you need to scale down the x and y sides so that the dart object points in the positive ‘z’ direction when the rotation is (0,0,0).