Applique
When fabric is inserted on top of your fabric. A single line is stitched around the border, then the hoop is taken out of the machine. The fabric on top is trimmed close to the single line stitching. Put the hoop back into the machine and a satin stitch will cover the raw edge of the cut fabric.
Stabilizer
A significant part of embroidery. Every project requires some sort of stabilizer to create a stabile platform for the fabric. There are specialty stabilizers for all sorts of fabrics from silk to leather. There is also tear away, wash away and cut away stabilizers. Additionally, for knit fabric there is iron on to prevent stretching.
Lace
One real nice feature about embroidery is you can create lace around other fabrics or on fabric. I had a customer bring me a sweater that was worn out in both elbows. So because I live in horse country, I took a lace horse medallion pattern and stitched up her elbow holes. When finished, it looked like the medallion belonged and added some pizazz to the sweater
Thread
I have found that the 100% polyester 40 thread works the best. But when you start embroidering, this can be an expense that has to be built up. I started with a small kit of 12 colors and within the month, the color expansion was necessary. So I ordered thread in the 1100 yard spool. I started running out of these spools pretty fast so now I am replacing empties with 5500 yard spools. I have found that rayon breaks too much and that a good polyester brand is the best. This is so I am not spending my time retreading machines.