References are key
Source plenty of references and polish up your Google-fu
Although the fire made in this tutorial doesn’t look exactly like a specific type, it’s that way on purpose; it’s meant to be an adaptable starting point for further work. When you get to that point you really need to be watching as many videos, or filming fires yourself. Study not just the colour and shape but the motion too, as well as things like how different temperatures and sizes of fuel vary the motion of the flame and smoke. You’ll notice that the more you look, the more things don’t act in quite the way your imagination believes them to.