Over the years, I've added personalized autographs to my collection in a few different ways.
The two most common have been:
Public Signings/Appearances- especially when there is a small number of attendees and/or you can pay a little extra for personalization. Some of these autographs are probably 15 years old at this point.
Devo is currently a coach with the hi-A Frederick Keys; he was nice enough to personalize earlier this year.