If it's an important phone call I usually ask the other person to email me with all the details we talked about. I usually make up some excuse about being out running errands so I can't take notes but it's 95% that their phone call woke me up and 100% that I don't ever remember anything said in a phone call.

It's my most critical skill to adapt the tone of my "mhmhmmm" to the tone of the word salad spoken by the other side