Simmer, uncovered, for at least 30 minutes. The chili should reduce a bit and have a nice thick consistency. If you have more time to let it cook, by all means let it simmer.
Toppings, toppings, and more toppings! Go crazy with it! My favorites are sour cream, shredded cheese, cilantro, sliced avocado, and a pile of tortilla chips alongside!