This is the first of many posts to come. I'm going to do a series on as many tips, techniques, and stitches of sewing that I can think of. They aren't in any special order. They will be categorized under the tab Sewing Basics at the top of the page.
Trimming and grading seams is important because it reduces the bulk of seams and makes the garment look more professional. Trimming and grading is used on necklines with a facing or lining, armholes, cuffs, collars, lined jackets, etc.
I made a small sample to show how to trim and grad. The green side is the inside fabric while the blue side with white chalk is the fashion fabric, or outside. I sewed a 1/2" seam and ironed it open.