How to rotate turret in enemy direction continously?

Questions & Answers
1

I have created an empty game object and turrets image which i have made a child object of the game object,whenever an enemy is spawned ,it beahves randomly doesnt tries to loook at the enemy direction,just rotates around itself randomly,i have attached my script to the parent game object,here is my script

   using UnityEngine;

   using System.Collections;

      public class Turret : MonoBehaviour 
      {

  private GameObject target;

  void Start(){

   }

   void Update()
     {
	if(target != null){
		transform.LookAt (target.transform, Vector3.up);
	}
	else{
		target = GameObject.FindGameObjectWithTag ("enemy");
	}
     }
         }
2

Did you try to do some debugging or logging?
Try to determine first if the target is actually ever acquired, put Debug.Log into the if (target!=null) {} section.
Then try to print out actually positions and rotations.
Also you could try to use Quaternion.Slerp instead of transform.LookAt, ee if it makes any difference