As you can see, you just need to be organised and prepare the steps beforehand. If you infuse the herbs for too long, the taste will get bitter or too intense. I like the fresh lime taste that hits your face as you drink the soup and so, I add them at the last step, into the bowls, not the pot.
Don't overcook the prawns.You can cook and serve this just before the meal, If your stock is already prepared, you need only about 5 minutes to prepare and serve. Another way to approach it is this: prepare everything else in the pot. When you are about to serve, add the trio of herbs, prawn meat and lime. There are alternative ways to make it once you understand this infusion concept.
There was once when I used bottled calamansi, and that was disastrous as it was too intense and lacked the fragrance of the fresh Thai limes. On another occasion, I added squid. I was clumsy and as the heads were not cut out or washed properly, the soup quickly turned black. I learnt then that the soup needs to look as appetizing as it tastes and most of it was wasted as none in my family wanted Black Inked Tom Yum. Neither did I.
Tom Yum Goong is best enjoyed accompanied by steamed rice. It can also be a starter soup. It is best savored in individual bowls rather than served along with the rest of the dishes as is normally done on family tables. This is just a matter of preference.
Get the basics right - appreciate the fresh taste of the trio of herbs - and you can experiment with other meats/veg but never crowd out the taste of the trio. Try adding squid, scallops or fish. You can opt to make a more intense stock. I also like to add a bit of chicken stock or bullion when finishing the soup. I sometimes use more prawns (especially when you blend the shells and heads) for a more prawny stock. The prawn based stock goes very well with the herby trio and if prawns are cheap and aplenty where you are, no reason why you should not be more generous with the use of prawns. You can use the heads and shells of 1 kilo of small to medium size prawns, and keep the meat for use in other dishes. Then use large prawn meat to serve. I sometimes do this if I am serving guests.
And don't even try to pair it with wine.