High humanity-rating older vampires
Although it's not explicitly enforced a general assumption is that as vampires age they will often lose Humanity, fall out of touch with human emotions, human perceptions, and the human race and become alien both as a natural consequence of society changing and their own inhuman nature and resulting psychological problems.
Ergo, if an older vampire has a high humanity rating, they have likely made an effort. They keep up with the latest trends. They have a psychologist. They put time, money and effort into interacting with human society on a regular basis - they go to raves, they play chess with old men in the park, they watch and care about reality tv shows. They might even work a job, go on dates, or collect action figures.
To portray a character like this, show this process in action. Have the party meet them as they are on their treadmill with a PA handing them a smoothie bottle and time-checking them, or they ask the party to pick up some promotional object at a job fair and bring that back in addition to their other task(s). Have them whip out pop culture references that are out of date, realize they are out of date, apologize, and drop instead something that only tweens use. Show the effort the vampire is putting in to remain 'current'.
Likewise, show the effort the vampire is putting in to retain empathy. Have them intentionally force themselves to do something less advantageous for them because it is 'right', or take a moment to intentionally feel the appropriate emotion.
Retaining humanity as a vampire is the process of practicing a quality which is no longer automatic, or rather, that is largely the best way to portray it. There are other options or means by which a vampire could maintain humanity, but they are generally more complicated and harder to portray. 'Putting some effort in' is the easiest to show and also often the most entertaining for the players (your audience).
