Do Some Ironing
Even with frequent trims, the ends of your hair can be difficult to manage. They're the toughest to manipulate into a perfectly smooth finish (and even tougher to get to flip up so they whisper "princess" while you walk).
You'll need to curling-iron it into submission. Upgrade to a ceramic one, which will maintain a consistent temperature. Loop the tip around the iron for a brief moment, gently pulling it through all the while. If you want to brush the ends afterwards, make sure to apply a bit of frizz-taming product first, and then brush lightly.
And finally, the easiest way to look like Kate on a budget …