I started with going from coffee to black tea, which is supposedly about half the caffeine... now I just skip tea sometimes. maybe i’ll stop it completely
Green tea would be a good next step - a bit less caffeine (although I'm sure this could vary between brands) but still satisfies the need for a nice warm drink. I've been having green tea for many months now (after quitting coffee) and I'm not even sure it's worth stopping - I don't get any of the anxiety that I'd get with coffee, for example.
Green tea can totally have more caffeine than coffee, especially if you re-brew like many people do. But the theanine in tea takes the anxious edge off.