> Use as light and as thick a fountain pen as possible. Also, very thin & hard pen tips may be nice but in my experience they make it harder to write.

I use Fine-Medium nibs (some fine nibs are too fine, and some medium nibs are too thick).

Amusingly, I've discovered recently that my handwriting is much worse with thick pens. I write better with pens slightly on the thin side (but not too thin). Of course, that doesn't mean it's better for my wrist!