As a costume designer and fabric artist I sew ALL THE TIME. Not everyday, but most. I sew fast and I sew well. Really, I consider myself an expert. I often shock people with my skill and knowledge because I'm young(ish) and look even younger than I am. But I don't know anyone that sews more than me- I've been sewing for 20 years, and almost daily for 10. I make a living from this stuff. I teach this stuff.
Now that I've convinced you all of my expertise, I want to impart some of my knowledge on you. I meet people nearly everyday that say they'd love to learn to sew. There's a lot of resources for learning the art, even from the comfort of your home. One thing I hear a lot is how confused people get by all the technical jargon. It's easy to pick up an easy sewing pattern for beginners, but not easy to follow when you're not sure of half the technical terms used. Below I've listed many of the most basic terms with a brief explanation of what they are.
running stitch- the most common of all stitches, straight, in and out through all layers of fabric.
hem- hemming is the process of folding over the edge of fabric and stitching into place so that the fabric can't unravel.
blind hem- a blind hem is a certain hem that the stitches are not visible, used most often for dress slacks.
baste- to baste something is to sew it together quickly with large stitches that are meant only to be temporary
lining/line- lining is an inside layer of fabric, not meant to be seen, but used to conceal seams for a neat finish, make a garment thicker and more durable, more comfortable, and slide on and off easily.
flat line- a certain way of lining that is only meant to make a fabric thicker and give it more body. Two fabric are sewn together around all edges, then treated as one fabric.
sack/ bag line- a way of lining that does conceal the seams and finishes edges.
hook and eye -very small closure that is a metal hook that secures to a metal C-shape.
finished edge- a fabric edge that will not come unraveled, a finished edge can be done in many ways such as lining, hemming or casing.
unfinished edge- a fabric edge that is raw and may come unraveled.
bar and hook- a closure that is a metal hook that secures to a metal bar. It is similar to a hook and eye but larger and more durable, used often at the waist of dress pants and skirts in place of or in addition to a button.
press- to iron. Many underestimate the importance of carefully pressing each seam as they sew. I know I did when I was a newb.
top stitch- a top stitch is basically a running stitch that is through all layers of fabric and visible on the outside of the garment
serge/overlock- a super-secure way to finish edges and/or sew together fabric and finish the edge at the same time. I serer/overlock machine is required for this. Most commercial clothing is serged. It is made of a complicated series of straight stitches and loops around the edge.
stitch length- the length of each stitch. The stitch length will be mostly determined by the type of fabric being used.
seam allowance- the narrow strip of fabric that includes the unfinished edge on the outside of the stitch line.
trimming a seam- cutting off the extra seam allowance on a seam that will be turned inside.
grading a seam- when a seam is on the outside edge of a curve, the seam allowance must be slashed up to but not through the stitch line to allow the seam to finish nicely once turned right-side out.
notching a seam- similar to grading a seam, but cut V-shapes out of the seam allowance to remove bulk when a seam is on an inside curve to allow a nice finish.
selvage edge- when fabric is woven one edge is self-finishing, meaning one edge of fabric will not unravel without finishing.
grain line- the grain line of a fabric is parallel to threads of woven fabric. When cutting out fabric it is essential to pay attention to this, fabric will become warped if not cut on the grain.
bias- a 45- degree angle to the grain line of fabric. All fabrics have a certain amount of natural stretch to them when cut on the bias.
darts- a dart is stitching a wedge-shaped fold of the fabric to give it shape to fit around a body. Used very often in making clothing.
gathering- a technique for adding fullness, a piece of fabric is stitched and then drawn up on the stitch so that small folds are created along the stitch line and the overall length of the piece of fabric is shortened.
pleat- another technique for adding fullness, fabric is folded back on itself and sewn into place.
casing- a fabric tunnel created so that a drawstring can be run through, often within a hem.
facing- fabric used to finish the edges of a garment so that no stitches are visible, like lining but only for one edge of garment, not the entire thing (like a neck or armhole.)
right side- the side of fabric meant to be visible and worn on the outside of the finished garment.