Make friends first. But don't make it a "just friends" thing. Act silly and stuff too, be somewhat flirty (act confident in other words, but not too cocky). Have intelligent discussion, exchange ideas about philosophy and pretty much anything. They love intelligent discussion. Be trustworthy and sincere.
You sound like my INFJ friend. :p Do I sound like my INFJ friend? I don't think so for some reason...he's a bit too smooth and superficial for me still, I would be way more sarcastic. Too much confidence makes me suspicious. I wouldn't be able to get the over-arching contrivedness of walking up to me with the intention of chatting me up.
"How dreadful!" cried Lord Henry. "I can stand brute force, but brute reason is quite unbearable. There is something unfair about its use. It is hitting below the intellect." ~ Oscar Wilde - The picture of Dorian Gray
Conk him/her in the head, throw him/her over your shoulder, and take him/her home. That's actually a semi-serious answer too. It's better than waiting for cues from someone who doesn't know how they work. You'll either get disemboweled (they don't like you) or they'll just go along with it (they do like you).
This. Oh and the friend but not the friend thing. Be open to ideas in progress. Have intellectual discussions, don't take it personally when you encounter something with them and they do the nostril flair - that is what the cretins drink - sort of look. Don't get offended that they need alone time doing alone activities. You need to breathe. We need to be alone. Same thing. Don't worry about them keeping strange hours or sleeping in spurts then being up. It doesn't require a doctor. Don't be a flake. God don't be a flake. As in, show up when you say you will, make commitments and keep them and write things down. DO NOT call me 5 x from the store to find out what I need after you offered to go in the first place. That's why they invented notepads and pens.
I like to rock n' roll all night and *part* of every day. I usually have errands... I can only rock from like 1-3.
The conversation has everything that gets to me...
2. Off the wall comments
Plus there wasn't the added tension of actually being asked out. I was offered a chance to go back to a place where we'd already met with no awkward, put-you-on-the-spot decision making... I'd have a whole week to think about it.