My goal this year is to learn needle turn appliqué. I hope by commenting this will be bookmarked for me. I wish I could figure out bookmarking on this site.
I used to needle turn everything. For a couple recent projects, I decided to machine-stitch my appliques to a lightweight lining (right sides together and then turn). Gloriously easier for everything except a design with lots of tiny pieces.
For each applique, I make a template out of cardstock -- easy to print on my printer. Then before I trim and turn my applique I set the template on top the stitching lines so I can correct any boogers before turning.
To sew those inner corners when using a lining, I'll put a pin in where the innie stops and just aim for the pin.
The lined appliques can be blindstitched, zigzagged, or even straight stitched on.
Sometimes I stitch around the applique, just inside the stitching line, and then proceed to do needleturn applique. That way there is a row of stitching that keeps the corners from raveling and I have a line to follow.
I will also sew a lightweight piece of interfacing or fabric , right sides together, and turn by cutting a small "slice" in the back of the applique. Then I press, and it's all ready to be appliqued, without any problems of fraying.
I use the ladder stitch for my applique, about four threads at a time until I get to the innie. I use fray block (which is soft) not fray block (which is hard) to prevent fraying in the cut, and I reduce the stitches inside the inner most stitch to one or two threads per stitch. The inner most stitch is taken into the applique then into the background. If you turn the piece over it looks like a tiny running stitch. When doing multiple layers, I will applique the top piece to the next piece as though it is the background, only then will I trace and cut that piece to applique to its background. I can have a whole rose appliqued and ready to put onto its final background.