I am trying to understand the tadka (tempering) technique or procedure Indian meals. Is the a specific order in which spices go in in order to avoid overcooking some which are more delicate? I understand that for example the cumin seeds will usually go in first. Some tadka also include cilantro - that would obviously go in towards the end. Is there a general procedure to follow? I would also be happy for some book tips that focus on the techniques used in Indian cuisine, not just concrete recipes.
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).