This drawing above was my original concept drawing for my Jedi costume. I had originally planned to do something funky with the tabards where they'd be one piece instead of two (as you can see below the obi/belt line). I wanted to put an accent like some tapestry embroidery or something in that panel below the belt. Then I wanted to mirror the "arrow" of the tabards with a point upward in the top of the belt, and use a large metal button in place of a buckle (since they actually buckle in the back). However, since I started working on the costume less than two weeks before I was planning to wear it I threw my concept notions out the window and just tried to do something simpler and more standard, as you can see from the photo on the right of what I actually ended up making.
Since the Inner Tunic is pretty well hidden under the Outer Tunic anyway, I figured I just needed a earth-tone top that suggested a "wrap" or "cross-over" of fabric. I found a Byers California brown stretch top that fit the bill perfectly for (if I recall correctly) something like $2 at Goodwill.
The Outer Tunic is made from an old bed sheet, folded in half. I laid it down on the living room floor and made an "angel" shape large enough to make the wrap tunic. I screwed up the sewing on the collar a bit, though, so there's a bit too much material there, but I wasn't going to attempt to fix it or I felt I'd probably just make it worse.
My Tabards and Obi are actually sewn to one another. I did that partly to keep things from shifting too much in the back when wearing the costume, but also because it makes it easer to dress in the costume without help. The tabards stop at the obi in the back, which is where they are sewn at an angle going up to the shoulders. the front of the tabards are loose. Obviously if you want the tabards to extend beyond the Obi in the back (like Qui Gon's did) you'll need to decide if you're going to attach them to the Obi in the back or if you're just going to have three separate pieces and let the Obi actually hold the Tabards in place. Some people also like to add buttons or velcro at the shoulders of the tunic and to the underside of the Tabards to keep them from slipping off the shoulders. I didn't need to do that because there was enough friction between the Tabard and Tunic material to keep them in place. The obi attaches to itself in the back with velcro. Like the Outer Tunic this piece was also made from an old bed sheet. Below is a photo of the Obi/Tabards I made and a diagram (click for larger) of how that was assembled.
I didn't make the pants. I found these at Goodwill for $4 and they were perfect for the costume.
My hooded Jedi Robe is made from blanket fleece. I'd read that the robes in the movies were made from blanket wool, which is expensive and scratchy so I wanted to make the robe out of something more comfortable. I got the blanket fleece on sale for about $2 yard. I bought 10 yards worth (an entire bolt - except mine was in four large pieces). These robes are frickin' HUGE and the hood is gigantic, the weight of which constantly wants to pull the robe off your shoulders. At the convention I had to ditch the robe during the room parties, partly because all that fabric swimming around me knocks things over and people step on it, but it was also VERY VERY warm.
(sorry I forgot to snap a pic)
I had a terrible time trying to find a pair of boots with less than 2 weeks to the convention. Frankly, had I not found any I'd have put the entire costume on hold until I did find a pair. I thought, since I was buying at the end of the winter season I'd find plenty on clearance. NO SUCH LUCK! I took time out from sewing to make three trips to various malls specifically in search of a pair of tall, brown, leather boots with flat (or low) heels and enough space to tuck the pants in around the top. On my third and final shopping trip, about to give up, I decided to walk out through Macy's. I normally would never have even considered Macy's since I simply can't afford to shop there. But literally on my way out I happened to walk by a clearance rack of nothing but boots at 75% off! Most were not my size, most were high-heel fashion boots - but tucked in behind some others was one pair with a low heel, the right color, with a neat buckle accent, and much to my surprise in my shoe size (a size I don't always see on the rack much less a clearance rack). I snapped them up for only $79 (retail price: $189). In case you're wondering they are Jessica Simpson "Brunella" boots. They were VERY comfortable for walking around all day and night at the convention, and I got several positive compliments on them.