Hahaha, was the first thing I found on Google when I was searching for the exact phrase. Just posting this cause its so undeniable funny and true, and also just to post something to fill my blog..... =)

Sometimes you just want to be left alone. Some people make you wish you could be invisible--whether it is the nosy woman behind you in the check out line, an ex, your mother, or the creepy guy who stops you in the hall everyday at work. If you get the urge to ignore people, follow these steps.

Steps

1. Use technology. A cell phone, MP3 player, and PDA are wonderful gadgets for helping us look busy and keep us blocked off from the people around us. Any time you want to ignore people, just pick up one of your trusty gadgets and tune them out.
2. Look down. In the street, hallway or office if you don't hear someone calling your name you can't offend them by not answering. Walk around as though you have some major business to attend to at all times, and if you are ever accused of ignoring someone just say "Sorry I didn't hear you."
3. Turn away. Really pesky people that won't take your silence as a reason to stop talking need to be ignored. Just turn your head and act like you are enthralled in the graffiti on the building next to you. If turning away doesn't solve the problem, then walk away. Catch another bus or train to your destination and free yourself of annoyances.
4. Use body language. Crossed arms and legs are a clear sign that you are not open for conversation. Scowl at anyone who tries to sit near you and never smile. Giving the signs that you are not welcoming any attention will help you ignore people.
5. Be a snob. Simply turn a blind eye to all that goes on around you. This will allow you to ignore the people in your general vicinity, but also the entire world. Don't watch television, don't listen to the radio and ignore to your hearts content.
   

Warnings

• You may eventually be totally isolated, so be prepared and make sure your situation is only temporary. Don't ignore the world forever!
• This can also hurt people so make sure you have a good reason, other wise you could make good friends with whoever and never know it!
  

From wikiHow