Found a potentionally good partner, but cant come up with good idea
Thoughts on how to proceed?
Maybe examining your cross-over of interests, abilities, knowledge, etc. will make something pop out.
Just start building SOMETHING. Give it a go, come up with a tiny idea and see what comes from it. Without knowing your abilities, etc. it's tough to know what your areas of interest may be.
We'd be good, because we have complimentary skill sets, and personalities.
So one approach to finding that idea is to try hard to not come up with an idea. Make that a goal and you may notice that ideas start flowing in that way. Individually, write down these urges, and focus on summoning the courage to face them.
Maybe HN readers will see where you could apply these skills and make suggestions.