Okay, okay, we're not quite to the dust generating point yet.
First off, Research!
Every project starts out this way: Several hours of research, which entails stalking Google image searches as well as forums such as www.therpf.com
(Replica Prop Forum) for references of your subject, from every which angle possible. Always
have your references handy when you're working. There are times when I have an impression in my head of how something should look, I make it, and only then do I look at my reference and notice that it's different in some fundamental way, forcing me to scrap my work and start over.
The above pictures are the best references for Tidus' Brotherhood sword. The first picture is best for figuring out the how the handle will look. There's a great sense of the roundness and depth of the handle's features, as well as the appearance of the blade as water. We'll come back to this reference in a bit.
The second photo is more useful for creating your pattern. It's a straight on shot of the side of the sword, and it shows the whole blade. You'll have to contend with Tidus, who is rudely standing in front of a portion, but it's an easy thing to follow the lines through to finish it up.