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.