Most Helpful Guy
There is no guarantee that you won't look like an idiot or scare them off, but if you want something then you have to be willing to take some risks in life.1
Most Helpful Girl
OK, this is just my opinion stemming from experience:
Women should flirt with guys and make it obvious that way that they like him.
But never ever tell a guy that you like him, it will ruin the chase for him. And no matter what guys love to chase.
Plus if he doesn't like you back you will be crushed. Happened to me and it was not fun.
If you make yourself friendly and approachable with a flirty smile, the guy that's interested will ask you out. If not - he is not interested.1