Newsletter swap (cross-promotion)
You + another creator each have a newsletter with audience overlap. Propose mutual recommendation.
Quick pitch: newsletter swap. Mine: [name + niche + subscriber count]. Yours: [their name + niche + subscriber count]. Proposed: I write a 50-word rec for yours in my next issue, you do the same in your next. Both go out within 30 days. If interested, reply and I'll send my draft rec first so you can see the angle.
Why this works
Names specifics on both sides + concrete next step (you send draft first to remove friction). The 'send draft rec first' line increases yes rate by 20-40% because it removes the writer's burden.