Show up to your friend’s half-empty open mic. Small crowds remember every face.

Support counts most when nobody else is supplying any. A packed room does not need you; a nearly empty one remembers every single face in it, permanently. The cost is one evening and a bit of awkwardness. What it buys is a friend who knows exactly who turned up when it was not fun.

Go to the small thing your friend is doing. Sit near the front and stay for the whole set. Say one specific thing about it afterward rather than a general compliment.