GUISkin.GetStyle
GetStyle(styleName: string): GUIStyle;
GUIStyle GetStyle(string styleName);
def GetStyle(styleName as string) as GUIStyle
Description

Get a named GUIStyle.

	private var b : boolean;

function OnGUI() { b = GUILayout.Toggle(b, "A toggle button", GUI.skin.GetStyle("Button")); }
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    private bool b;
    void OnGUI() {
        b = GUILayout.Toggle(b, "A toggle button", GUI.skin.GetStyle("Button"));
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	private b as bool

	def OnGUI() as void:
		b = GUILayout.Toggle(b, 'A toggle button', GUI.skin.GetStyle('Button'))

Another example:
	// Simple custom editor that when any SimpleExampleScript
	// is detected in the inspector, it shows it as an IntSlider
	// and a GUILayouted bar.
	
	@CustomEditor(SimpleExampleScript)
	class CustomEditorExample extends Editor {
	
		function OnInspectorGUI() {
			// Get the place of the next available position in the script
			target.damage = EditorGUILayout.IntSlider("Damage:",target.damage,1,100);
			ProgressBar (target.damage / 100.0, "Damage");
			
			target.armor = EditorGUILayout.IntSlider("Armor:",target.armor,1,100);
			ProgressBar (target.armor / 100.0, "Armor");
			
		}
		
		// Custom GUILayout progress bar.
		function ProgressBar (value : float, label : String) {
			var size : Vector2 = GUI.skin.GetStyle("ProgressBarText").CalcSize(GUIContent(label));
			var rect : Rect = GUILayoutUtility.GetRect (size.x, Mathf.Max(size.y));
			rect = Rect(rect.x + 4, rect.y, rect.width -8, rect.height);
			EditorGUI.ProgressBar (rect, value, label);
			EditorGUILayout.Space();
		}
	}
And the script attached to this editor script:
	// SimpleExampleScript.js
	// This is not an editor script.
	
	var armor : int = 75;
	var damage : int = 25;