A useful common pattern is that haal is generally indefinite, while dhu al-haal is definite.
جَاءَ الْوَلَدُ ضَاحِكًا
- الْوَلَدُ is definite and is the ذُو الْحَالِ.
- ضَاحِكًا is indefinite, mansub, and is the حال.
This is a recognition guide expressed as generally, not a claim that every possible Arabic sentence must look identical.