Get Online Early
If you're planning to pre-order the iPhone Xs or iPhone Xs Max when pre-orders go live at Midnight you'll want to make sure you're on early. Getting online at 11:59PM isn't a good idea.
If you can manage it, we recommend hopping online at least 30 minutes before iPhone Xs pre-orders start in your time zone in order to get situated and make sure you've got everything lined up ready to go.
While you might feel prepared, there's a chance you've overlooked something important regarding your pre-order. You'll also want to get acquainted with the website you'll be pre-ordering from so that you know where to go when pre-orders begin.
While Apple's website is easy to navigate, carrier and retailer websites are often confusing and convoluted. If you're spending time figuring out how to properly navigate through the website at 12:02AM, you might not get the model you want in the timeframe you want.
We also recommend logging into whatever site you're planning to buy from ahead of time so that you're ready to go.