Hi Burn, I wish i had something useful to contribute since you had asked, but I'm not much of a seamstress, and tend to hit n' miss my way to success ^^; Here's a couple random bits i can toss into the mix though
Found out a day or so ago from a friend about using "stabilizer", which helps reduce the curling along the edges of the outfit from the fabric stretching when you run it though the machine. Since you're using a zig zap pattern, she recommended water soluble stabilizer that can be dissolved, but it you're doing a straight stitch, you can use wax paper that you can easily tear off, to help prevent that annoying curling
With the red belt, I made a cumberbun looking thing, and hooked it on with bra strap looking loops to make it easier to put on (vs. wrapping it on). Sorry its a bit vague, but i cannot remember official terms to save myself ^^;
I also like to add an layer of interfacing into the inside and an inner layer oof tunics and well... just about everything outside of the cape (and interfacing if the layers are thin) to give it more "body" and weight, which I feel adds to the realism of an outfit.
if you wanna see some epic sewing info and such, check out my friend Cathy's facebook page.. she has a WEALTH of information, and insane skills to boot!
https://www.facebook.com/gstqfashions
Vincent, you can alternately use a saw, some files (they're faster than you think!) glue, and sandpaper! I just happen to have more equipment around and such, but its not absolutely necessary. Poplar is a lil' soft, but doesn't have the ultra distinct grain that say, Red oak has. and its easy to carve up, and its pretty even in terms of hardness (like, pine will give you waves if you hand sand w/o a sanding block)
you can find 1/2" craft planks at Lowe's & Home depot for a relatively decent price!
hen finishing, you can prime it, spray it with a silver (or paint it with siiver acrylic paint), then go in with some black and do a lil' weathering. I really Rustoleum hammered metal spray, with powder rubbed on (since i happened to have powder). but the powdder isn't necessary! Its nothing more than personal preference
I'll always recommend getting a Dremel tool (you'll find a millikon uses for that thing!). don't bother with rechargeable ones, get the corded ones!