How does the process of tempering in indian dishes generally work?
The general rule of thumb is to put spices that burn easily in the end. Black mustard seeds are often added, in which case add the mustard seeds to hot oil first. Once the mustard seeds stop popping, turn the heat down, add urad dal (white lentil), dried red chillies, cumin, and turmeric. Of course, your tadka may not have all ingredients that I've listed (or may have others that I haven't). I generally add turmeric last because it burns the most easily. South Indian tadkas often add fresh curry leaves. Those can be added right after the mustard seeds (they splatter, so one has to be careful).