I look at it as making my intentions clear, being honest and it gives them a choice as opposed to the old fashioned, wait for the right moment and kiss her method. That shit is lame and sneaky.

I've thrown the make out question from pretty deep in left field and it has worked way more than I could've imagined, if someone told me this many years ago. But YMMV.

But the signs should be there. If a girl touches you, it's a pretty good indicator that she's interested. I still regret the times a girl put her head on my lap or her feet on my lap, asked for a massage, while watching a movie/hanging out, just to find out later that she was totally interested in me and I didn't ask her if she wanted to make out when I had the chance. When I totally could've hooked up with her if I did. There's other subtle gestures and touches that could indicate interest but I just pay attention to the more obvious ones.

I'd weigh my interests as being more important in terms of attractiveness but appreciating someone else's interests is good too.. But it's the passion in those interests that a potential ate is going find attractive. Shows that you have drive and all of that jazz, perhaps they don't know about your interest but your drive and motivation is attractive. Definitely show interest in their interests but you may not know a lot about the subject/activity so I would stick to curiosity and not overdo it too much. Don't want to come off needy and it hasn't hurt me too much by being different or opposite. I'm not sure if this advice is universal or just applies to me though.