For instance, common examples of indirect approaches involve asking for the time or where the nearest Starbucks is. These opens don't suggest any attraction and the answers are likely to be "polite". But what about approaches that convey some interest but aren't necessarily "direct" acknowledgements of attraction? As an example, going over to someone with their books open and asking what they're studying. This isn't a random question and the person is likely to understand that you're showing some interest in them - if you have even the slightest bit of suggestion about you. Or at karaoke, I'll go over to someone and ask them what they're singing/of if they're singing - and attraction is immediately understood. And more than that, there's almost instant rapport building.

Does anyone make a distinction between those kinds of approaches and generic indirect ones? And if so who can I read on this?