How do I make my friend Notable?
You'll need to draw an "A visit from Slowcake's Amanuensis" card. Amongst its options is "Recommend an unknown acquaintance", which is unlocked when you have at least 2 Notability. It's in game description is:
This will transfer a single point of Notability from you to a friend with zero Notability, allowing them to summon the Amanuensis.
Unfortunately the Amanuensis card is infrequent. If your Making Waves is high enough to reach the next Notability level, you can still draw it from the "Attend to matters of society and scandal" option in your lodging.