Dulce de leche is one of the best things to make when you're in your kitchen for a few hours and can check in on it periodically. While it takes a bit of time to make, it's mostly a set it and forget it thing - just give it a stir every once in a while. Best of all, it keeps in the fridge for over a month, so it's worth the effort! Use it to top berries, drizzle over whipped cream, or as I do for this taco night by making a dulce de leche adffogato.
As you're making it, the caramelization and the color can take a while to see - you may think you're not doing it right. But all of a sudden (sometimes an hour + into making it) the milk mixture will start to become golden, gradually deepening in color and thickening in consistency. If yours is taking a while, don't be discouraged (and don't bring the heat back up to make it boil!).