Wow, that's a really wonky image. Oh well! You get the idea. Pin your material, right sides together, along one edge, then sew. I tapered my lining material to be a little smaller then my outer material, that way, when turned and flipped, the seam lines would not show. That's a little couture technique, free of charge.
Press the single seam you just put in, THEN go back and pin and sew the other side of the tie. This will make your life easier. Do you trust me? This is also the perfect time to sew up the narrow end of the tie.
Once you have sewn the narrow end and both long edges, turn and flip your tie right side out. Pay careful attention while pressing, making sure to keep the lining towards the inside of the completed belt. When you're done, check to make sure your two ties match up in size. You will want the "fake" tie to be a little bit more narrow then the real tie. Don't sew up the fat end of the tie. There is no reason to.
Slide the fake tie into the end of the real tie. You will be able to slide the point of the fake tie to the little tacked stitch.
Flip and pin in place. No here's where you get to make a decision: You can top stitch around the real tie, hand stitch to hide your stitching, OR do like I did and run a stitch line down the center of the tie, right were the belt will cover when tied (see photo below). I also ironed a fusible hem tape around the edge of the real tie to hold it in place.
When I tried my obi belt on, the back about drove me nuts. Oops! I should have thought of that first! NEXT time I'll create two separate belt pieces and do something more like this. But for now, I just added a welt opening and that fixed my frustration.
Since this was an afterthought, I had to seal down the raw edge of the welting. A piece of fusible interfacing did the job quite nicely, thanks! I'm not proud, but no one will ever know when I am wearing the belt. And it's not like I'm going to post this online...oh...wait!
Ta da! This is me, after a full day at the bridal shop. I could have tied the belt into a bow in the front, but I preferred to slide the ends into the welt opening on the back. Not too shabby for a $3 tie, huh? And yes, I am aware that my dress is looking a little large. I'm blaming it on eating healthier. Seriously, I JUST purchased that dress a few weeks ago and it fit fine! Perhaps you're witnessing a magic trick called: The Disappearing Green Mommy! "A-la almond butter, and apple slice sandwiches", said in my best Mumford, from Sesame Street, voice.