Preheat the oven to 350°F. Line a rimmed baking sheet with foil (if you want to do your loaf freehand - otherwise you can use a 9x5" loaf pan.
Heat a drizzle of oil in a medium skillet set over medium heat and sauté the onion and garlic for about 5 minutes, until soft. In a large bowl, combine the meat, sautéed onion and garlic, bread crumbs, tomato sauce, egg, Worcestershire sauce, salt, and pepper. Mix everything together with your hands until it’s well-blended; just don't work it too hard or it could get tough. Shape the meat mixture into a loaf shape that’s roughly 9x5" on the baking sheet or press it into a 9x5" loaf pan.
To make the glaze, stir together the ketchup, sugar and mustard in a small dish. Brush the loaf with half the glaze and bake for 30 minutes. Brush with the remaining glaze and bake for another 30-45 minutes. (If you have a meat thermometer, the internal temperature should read 160°F.) Let the meatloaf rest for about 15 minutes before you cut it.