Objective: Sew a complete, saleable two-piece fabric coaster from start to finish using the straight stitch and quarter-inch seam allowance.
A coaster is the ideal first product because it uses every core skill you already have—straight stitching, backstitching, and maintaining a seam allowance—in a project you can finish in minutes and sell in sets. The construction method is 'sew-and-turn': you place two fabric squares right sides together (the patterned faces touching inward), stitch around the edge leaving a small gap, then flip it right-side-out through that gap so the raw edges hide inside. On the MC6650, set a straight stitch (pattern 1), stitch length about 2.5mm, and use the quarter-inch line on the needle plate or the quarter-inch foot as your edge guide. Lower the needle into the fabric before pivoting at each corner so the line stays continuous. Clipping the corners at a 45-degree angle before turning removes bulk so the points come out sharp. A final topstitch close to the edge both closes the turning gap and gives a crisp, professional look buyers expect.
Example: Cut two 5" squares of quilting cotton. Stack them right sides together, pin. Starting on one side, backstitch, then sew a 1/4" seam all the way around, pivoting at each corner with the needle down. On the last side, stop about 2" from where you began—this is your turning gap—and backstitch. Clip all four corners diagonally. Turn right-side-out through the gap, push corners out with a chopstick. Press flat, folding the gap's raw edges inward to match the sewn edge. Topstitch 1/8" from the edge all the way around, which seals the gap. Result: a finished 4.5" coaster.
Try it: Make one coaster following the example. Time yourself. When done, measure it: it should be square, corners should be reasonably pointed, and the topstitching should run an even distance from the edge. Make a second one and try to match the first in size and stitch quality—consistency is what turns a craft into a product.