Readup on tutorials that are on websites like this one. Tech forums has some really good tutorials that explain almost anything you'd need to know about hardware and configuration. Well not EVERYTHING, but it is one of the best places to start.
Next I would suggest purchasing a book. Find a recent hardware book at Barnes and Noble or Borders and read up. While I realize a lot of people try to avoid purchasing a book I personally think it will be your best resource. While websites are great for starter information or referencing, not all information on the web is as accurate as it should be (not saying publishing a book makes you 100% right) and a lot of sites assume you already know a thing or two about hardware. Purchase an A+ book by Mike Meyers, he has some awesome tutorials and his books are extremely easy to follow (for both veterans and new people alike).
Next, get your hands dirty. While I would definately suggest reading up on your materials and getting educated first, actually taking a computer apart and putting it back together will furture your knowledge a great deal. But without prior knowledge from reading you could injure/kill yourself and taking something apart without knowing what does what within the computer itself doesn't provide much education.
Finally once you truely feel you are well versed in hardware continually review and read about hardware. Within this industry standards and hardware profiles change on an almost weekly basis. While you don't need to keep up with which video card is the latest and best, you should keep up with industry standards like PATA vs. SATA, usb 1.0 vs. 2.0, things of that nature. And of course reviewing ensures you keep the knowledge instead of forgetting 6 months later.
1)look around online like this website for tutorials about hardware and hardware configurations
2)purchase a good book, my suggestion would be one from Mike Meyers - since the industry changes pretty often ensue you purchase the latest book
3)get your hands dirty and take some computer apart
4)review and continue to read up on material
