First, read about the history of the word ‘hacker’. WIRED magazine had a great article last month that touched on how the word has become tarnished- http://www.wired.com/magazine/2010/04/ff_hackers
Second, if you are serious you must learn whatever it is you want to hack inside and out. That may be operating systems or your Wii or maybe your dryer to make it tweet when the clothes are done. Learn everything you can about it and then you can start making it do what you want it to.