If in a hurry, Place the bowl of egg whites in lukewarm water till the whites comes to room temperature.
The bowl and the whisk should be clean and dry and free of any grease or else the meringue will deflate.
In humid conditions, or when raining, baking time could take longer.
If your oven doesn't heat evenly or if using a smaller oven, rotate the tray once half way between baking.