I’m not yet 30 and I think it’s good applicable advice. I think you can actually practice a lot of these skills by making friends. The difference between romantic and platonic isn’t that big.

So I think the question could be refined a little. Eye contact helps build connection between people, but it’s not the only piece of the puzzle. Maybe a better question is “'How do I communicate more empathetically?”

There’s another question; “How do I let someone know I’m interested?” This question is related to the first in that trying to get close to another person (being vulnerable with each other) and communicating your feelings is how you let someone know your interested.

TLDR: get to know them and tell them you’re interested. If they say they’re not interested you can probably still be friends since you already got to know each other. Empathy and humility/vulnerability are key in building relationships.