(Ooops! I didn't finish this before I posted it last night, sorry.)
This is a tip for cutting out knit t-shirt style patterns without having to open the fabric to a single layer or cutting on the fold. I remember it from a Stretch-and-Sew class that I took years ago. It works for tops that have both left and right sides rather than a one side of the front/back placed on the fold.
When you have a pattern where the front and back are the same except for the neckline, trace the front neckline onto the back pattern piece. I also place a piece of clear tape near the CF and back neckline intersection to offer a little support to the pattern paper. With your fabric folded (just as it comes off the bolt) lay the back pattern piece out on both layers and cut following the back neckline. Remove the back piece but keep the pattern on the front. Cut out the front neckline stopping about 1/2" from the CF intersection. The pattern remains in one piece and you don't have to fuss with all that arranging to cut the pieces out on a single layer.
I've also started using this method in places like skirt/dress hems. You can cut the shorter length but keep the longer length connected to the original pattern piece. I've done some experimenting using it with multi-size patterns too but at this point I'm not sure it's worth the effort.
(The photo is supposed to connect you to my blog where I put the pictures - hope it works!)