Free-Form Bread Baking..?

Most of my life I've baked bread in a bread pan. Just as this year's heatwave began, I developed a new sourdough starter for myself (I'm a sourdough waffle addict). I've tried a couple of times lately to bake a loaf of bread (sourdough and other varieties) on a sheet rather than in a pan and each time the loaf tends to spread out and look more like Focaccia than the artisan-like loaf I hoped for. Any tricks, techniques or tips I could profit from? What would you say I am doing wrong and how do I correctly create a free-form loaf?