Most swap advice stops at how to find a partner, which is the easy part. The hard part is that plenty of swaps run fine and bring almost nobody, and it's usually the copy rather than the size of the list.

Most newsletters stop growing somewhere between 1,000 and 5,000 subscribers. The fix isn't more content — it's collabs. But there are seven distinct types of newsletter collaborations, and most creators only know one. Here's how to pick the right 2 for your stage.