As an author, I had the added issue of sometimes only knowing someone's pen name, and sometimes only knowing their real name. I was sending Christmas cards to someone for 3 YEARS before discovering she was a very good friend. Who I'd only known by her pen name. 😃
We had a great laugh about it. And my trick is to always make a point of greeting people by asking about what I do remember about them. (For that friend, it was asking if she'd ever found the cat that had gone missing the last time we'd been at a conference. ) They're much more forgiving about forgetting the name if they know you remembered *them*.