I am not aware of a process or best practices in this field, but off the top of my head, here's some ideas:
- Don't talk of cross promotion initially, but offer to meet just to talk about what you can learn from each other, and see where it goes from there (maybe nothing, maybe you'll learn something, maybe cross promotion, maybe you'll hit on an even more mutually beneficial cooperation).
- If you do just want cross promotion and nothing more, make the first move - create your blog / newsletter / integration design / whatever already, before you approach them. Let's be honest - which makes you hungrier, "I sell sausages for $1" or "Look at this sausage, doesn't it smell great"? Even if you don't make them hungry, you'll at least show that you're serious and aren't trying to take advantage of them. That effect will be the greatest if you already release your part of the promotion before approaching them, but if that makes you nervous you could also create it and wait until you have a deal before releasing it.
Good luck! If you don't find the advice you're looking for (again, I'm not aware of any established best practices myself) and you're still nervous about it, perhaps practice it with a smaller SaaS first - they have less to offer, but you have less to lose.
