Lots of good answers here already. In brief, it's about relationship building, not tricks. Having said that, they are helpful tools on the way. A new awesome tool you should look at is Conspire. It's a bit like LinkedIn, but more intelligent when it comes to networking and relationship building, in my opinion. Here is another "tool" you should always carry with you. Never, never leave a networking meeting without asking for one additional relevant introduction.

Hi. If you are based in DC, network, network, network. Tools like LinkedIn or Conspire might be of help to trace your path to your target person, whether or not you are in DC. If you are not based in DC, make trips here and network. Once you have found a path, then you need to consider how to approach the said person. Ask your contacts on the way for insights. Are there rules that might impeed said person to communicate with you? If yes, what are ways around them? More often than not, there is a way. Is this the kind of person who will respond to an awesome (give and take) "cold" email? The kind of person who will only meet with you to repay a favor? Read up on said person as much as possible, there might be relevant nuggets out there about him/her. Make it easy for people to help you! Anticipate or ask them what you can do to facilitate the intro they might be able to provide for you. Most importantly, as a practice, help people around you. They will be happy to help someone who has helped them in the past.