(C#) Rotate Object over Time

I need an object to to rotate over time. Here is my code that rotates the object.

using UnityEngine;
using System.Collections;

public class CrouchTesting : MonoBehaviour
{
//Variables Start

//Public Variables
public float xRotation = 90.0f;
public float xRotation1 = 0.0f;
public float RotationSpeed = 2.0f;

//Private Variables

//Variables End

// Use this for initialization
void Start () 
{

}

// Update is called once per frame
void Update () 
{
	if(Input.GetKey(KeyCode.LeftShift))
	{
		
		transform.eulerAngles = new Vector3(xRotation, transform.eulerAngles.y, transform.eulerAngles.z);
	}

	if(Input.GetKey(KeyCode.Z))
	{
		transform.eulerAngles = new Vector3(xRotation1, transform.eulerAngles.y, transform.eulerAngles.z);
	}
}

}

This is when I get stuck.The script works fine like this but it rotates straight away to the angle. I tried to use the rotation speed like this “transform.eulerAngles = new Vector3(xRotation, transform.eulerAngles.y, transform.eulerAngles.z) * RotationSpeed * Time.Deltatime;” But that Is not working. I googled it and nothing cam up.
I do not need a code but examples would be nice.

I think that it is a newbie mistake but I dont know how to do it.

If anyone could help me it would be greatly appreciated.

Thanks in advanced :smiley:

Infinite Gamer

Try out transform.Rotate() - Unity - Scripting API: Transform.Rotate

transform.Rotate ( Vector3.up * ( RotationSpeed * Time.deltaTime ) )

or this which seemed a bit easier for me
transform.Rotate (new Vector3 (Time.deltaTime * rotationSpeed, 0, 0))