What is the hardest part of finding partners to promote your product?

One thing I kept running into while building PartnershipIntel.com:

Most founders know partnerships can work, but the hard part is not always "doing outreach."

It is figuring out who is actually worth reaching out to.

For example:

- Which newsletters already accept sponsors?

- Which creators reach your actual buyers?

- Which SaaS tools are complementary enough for co-marketing?

- Who is the right person to contact?

- What pitch angle is better than "want to collab?"

Curious how other founders handle this today.

Do you use spreadsheets, CRM tools, manual research, intros, agencies, or something else?