The essential parts of a knife are the blade and the handle, so this is where you should focus most of your efforts. If you want to spend time on guards and pommels and such, that's good too. I don't make them because I don't have access to soft metal (brass, copper, aluminum) and I don't have a band saw. For the design of this knife I had a freehand rendering that I drew in English class under my desk that I used as a template. I liked the basic proportions, but I needed to increase the scale by 75%. This made the knife too big for graph paper so i had to tape some together.
I started with the handle. Working off my original sketch and with lots of measuring, i drew a full scale rendering of the handle. To make curves I draw dots at the correct measurements, then connect the dots with a French curve. This is where a lot of personal preference comes in. Design what you like and what looks good, it's your knife!
Most hardware stores I have been in carry brass and aluminum rod for welding and other applications. The brass rod for example can be cut into lengths for use as brass pins to hold the handle on.
I have just started making custom knives as a hobby which I enjoy and if someone is interested in getting started, there are many helpful instructional videos as well as books on making knives nowadays.
My own personal suggestion is getting a DIY kit online or from a knifemaking supply store if there is one near you and putting one together, refurbish a broken or old knife or customize an existing knife. This will familiarize you with the tools and give you an idea of what goes into knife construction.
Then you can progress to complete customization including learning how to forge your own blades or if you prefer you can use the material removal method, there are advantages and disadvantages to both methods.
It's satisfying to make a knife which is unique and has all the features you like in a blade! Good Luck!
The center of the blade hollow?
You actually don't need a band saw to cut those parts out. You can make do with a coping saw (check any hardware store, they're usually around $10 to $15) with a metal cutting blade (a few dollars more). Then you just need to find the brass, copper, whatever (ask around the hardware store while you're in there). Good luck!
You might check out the link below for fittings. He only charges one price for shipping, no matter what you buy, and he's real friendly. I've bought several things from him and have always been happy with the experience.
http://www.ragweedforge.com/BladeCatalog.html
And I didn't say it before but thank you for the Instructable! I enjoyed reading it.
(oh, and there are NO misspellings in this note!)