I've always found that "taking out" instead of "asking out" girls is best and almost foolproof in result unlike the latter. My technique revolves around the hiring or borrowing of a van with a sliding door. You will need someone to drive this van for you. You will also need some rope.
Next, scope out your chosen girls behaviour for a week or two. Look for patterns of times of when she is alone, out of the sight of others. When this is established, your moment chosen, drive up in your van, sliding door open and depending on your skills, either stop the van and grab your lady or grab her at high speed and throw her in the back. High speed is preferable for obvious reasons of reducing the time of being seen.
Once in the back of your van, tie your lady up with the prescribed rope. You don't want to lose your lady at this point! Take her home, and place her in a makeshift prison. I've found the cuboard under the stairs to be most suitable.
Finally, give yourself a pat on the back, you're now proud owner of a relationship. You didn't even have to go through the risk of being turned down.