Put the sugar in a pot, on medium or even low heat.
Let the sugar melt and caramelize slowly. Don't add water, the caramel will form on its own.
To stir and avoid that some parts burn, don't use any spoon, just gently shake the pot.
Be careful not to burn the caramel, it can go pretty quickly. If you have a cooking thermometer, the ideal temperature is between 239°F (115°C) and 266°F (130°C).
The caramel should have a nice brown color. If it is too dark it well be bitter, and too light means a lack of taste.
Use the caramel right away, it gets hard quickly.
There you are, your caramel is ready!