I used to think that *showing interest* was to ask out/make first move/start conversation,ect first. Basically because after getting NO attention from any guy for years, I was bored with it. I didn't realise that guys actually like it when you flirt with them! No wonder I wasn't paid attention to!
Sounds daft? If a guy you like has came to chat with you, it's gonna be exciting for him to see you with a big smile on your face the whole time, and you paying attention to him, keeping a good(but not scary) amount of eye contact and perhaps leaning in a little bit or touching his arm while he talks, sounding happy at what he says, ect. I didn't realise those things would be effective, til I thought of the opposite action. Looking depressed/bored, not really looking at them, keeping your distance, avoiding touch, not saying much in a dull tone of voice....for me that's when I realised how much stuff like initiating conversations and things didn't matter(men should be encouraged to do that stuff anyways!) I don't like dragging up the courage to call a guy, especially when they don't feel like talking. It feels a lot more fun just to be perky and flirty with a guy! lol.
So yeah, while it might seem that you're not interested if you don't call first or text first or start the conversation (though I guess you WOULD say hi to them in the street or something), it isn't if you flirt with them when you do have contact with them.
Damn I sound like the flirt ambassador or something.