The safest way I’ve found is not doing 1:1 swaps at all, instead, I focus on relevant partnerships, where there’s actual value for both readers and search engines, for example, I might write a guide on “SEO for Photographers” and naturally link to a photography resource site, then later, they mention my SEO agency on a tools page or blog post, not as a trade, but as mutual value.
Another strategy that’s worked for me: triangular exchanges, site A links to Site B, B links to C, and C links to A. When done thoughtfully (and not all at once), it avoids obvious patterns, context is everything. I avoid anything that looks like keyword stuffing in anchor text, branded or generic anchors seem to be safest.
I also never rush this stuff, spreading link exchanges out over time, keeping them embedded in high-quality, fresh content, and mixing in nofollow links all seem to help.