One of the most common mistakes when making a spicy soup, such as chilli, is that it may wind up being too spicy. A soup that has "too much heat" can ruin the presence of other flavours. There are several ways to remedy a soup that is too spicy, and none of them are very difficult or time consuming.
Prepare another batch of the soup in a spare soup pot, using the same directions and ingredients as the original recipe, but leave out the chillies. Once finished, mix the batch that is too hot into this new batch to the degree you would like it spiced.
Add tomatoes or tomato sauce, cornbread mix and even small bits of bread to taste in order to help tone down the spiciness. If you choose to use cornbread mix, add it in 2 tbsp increments and check the spiciness and grittiness of your soup. Each of these ingredients soaks in the spicy oils of chillies, and can even work to counteract them.
Top the soup with basic dairy products such as sour cream and cheese. The base, rather than acidic, nature of these products help to counteract the acids and oils present in chilli spices. As a last resort, you can also add milk to your soup, but add this only in small increments before checking the soup, for it can quickly spoil many of your soup's flavours.
Despite your best attempts to cool down a spicy soup, some guests may still consider your soup too spicy. It is a good idea to serve spicy soups with grated cheese and saltine crackers on the side so that your guests have the option to add these spice-cutting ingredients to their serving of soup.