Add enough oil to a medium pot so it is about an inch to inch and a half deep. Set the heat to medium and bring the temp up to 350 F/176 C or a little bit less, but not hotter than that.
Mix the flour, salt, pepper, and garlic powder in a small bowl with a fork or whisk, or sifter.
Cut the cheese into about half-inch wide by 2 or 2 1/2 inches long pieces. Or to make it easy just use string cheese mozzarella and cut each stick in half.
In a small bowl whisk together the eggs and the milk.
Dip the cheese in the egg wash, then into the flour, then back in the egg wash, then in the bread crumbs, then in the egg wash one more time, and back into the bread crumbs. This creates a thicker outer coating which helps prevent cheese leakage when frying. Place the stick on a pan or plate lined with parchment paper or a silicone mat.
At this point, you can freeze the mozzarella sticks for 30 minutes to an hour before dipping. If you plan on doing that, don't preheat the oil yet. Also, you can freeze them for long term storage, and only fry some when you want some. But freezing isn't necessary, although it helps a bit to prevent the cheese from oozing out. I get impatient so I don't always freeze them.
If you froze them, now heat the oil to between 325 F and 350 F. (162 to 176 C) Gently drop 3 to 4 sticks in the oil and allow them to fry for 30 to 45 seconds, until nice and golden brown. Don't overcrowd them. Remove them with tongs or a spider ladle and place them on a wire rack or plate lined with a paper towel.
Serve them as is or get a size of pizza sauce or marinara sauce to dip them in. Enjoy!