Step 1Drape the Fabric

Fold your muslin in half lengthwise, and cut a T-shaped slit in the fold for the head to fit through (the “leg” of the T should go in the front, as shown in the photo).

Step 2Pin the Muslin

Pin the muslin to the wearer so that it lies flat. On the front, you should pin under and above the breasts in a straight line. You may also need to pin into the armhole or even the neckline to make it all lie flat, but any additional darts that you pin should all point towards the highest point of the breast on each side. On the back, pin halfway between the spine and the side of the body, especially at the waist. You’ll probably also have to pin from the top of the shoulder to the shoulder blade, and possibly also into the armhole. Don’t forget to pin both sides, too.

Because I’ll be making a strapless dress in the end, I’m not paying any attention to the neckline or armholes. If you need them for your project you’ll want to be more careful in shaping those than I was.

Step 3Remove the Muslin

Take your sharpie and trace along the pins on one side, front and back. That will serve as a reminder of where the pins were when you make the pattern later. Remove the pins and carefully take the fabric off of the wearer to avoid stabbing them with any of the pins.

Step 4Trace the Pins

Get your Sharpie out again and trace around all of the pins, front and back. When you’re done, remove all of the pins.

Step 5Iron

By now, your fabric will likely be pretty wrinkled. This will make it hard to work with in later steps, so you’ll want to iron it out. If you’re using cotton like I did, turn your iron to the highest setting and use steam. Otherwise, use the right setting for the fabric you’re using.

Step 6Cut the Front

Cut the sides of the front, following the lines where the pins were. The lines are likely crooked and wobbly. If so, just cut in smooth curves close to the drawn line.

Step 7Cut the Armhole Dart

We don’t want a lot of darts in the final pattern, so we’re going to add all of the extra darts to the shoulder dart. The instructions here show you how to remove an armhole dart by adding it to the shoulder, but the same instructions would apply to a neckline or any other dart.

We’ll be working with just one side of the front, so fold the front in half and cut it apart. Then, cut along the line of the dart closest to the shoulder dart, as shown in the photo.

Step 8Slash the Shoulder Dart

We need to spread the shoulder dart apart in order to add the armhole dart into it. So cut down the middle of the shoulder dart as shown in the photo.

Step 9Spread the Shoulder Dart

Now pivot the shoulder dart open by meeting the cut line of the dart you’re removing to the other line of that dart. Tape down the cut edge to the fabric.

Step 10Cut Out the Shoulder Dart

Now that we have the final width of the shoulder dart, we’ll cut it open along the drawn lines. Again, these lines are likely kind of wobbly, so just cut over them using straight or smoothly-curved lines.

Step 11Cut Out the Waist-Hip Dart

Cut along the other lines of the front piece, smoothing them out as you cut. You should end up with a shape similar to what you see in the photo. Again, I don’t need any neckline or armhole shaping, so those aren’t reflected in my pattern.

Step 12Smooth Out the Front

Upon closer inspection, I noticed there were bumps near the waist darts. If I sew this line as-is into the final dress, it will look like a bump, so I cut it off. Hopefully this will help the final dress smooth out the bride’s waistline, with the help of some boning. You should also examine your front piece for any unusual lines that are begging to be smoothed out.

Step 13Cut Out the Back

Cut the back piece in half along the center back. If you pinned out an armhole dart, follow the instructions above to add it to the shoulder dart. Separate the back into center back and side back pieces along the darts. Do the same for the front, and you’ll end up with four pieces that should look similar to what you see in the photo.

Step 14Trace the Pieces onto Cardstock

Trace around all of the pieces onto cardstock or bristol board, and cut them out. As shown in the photo, use a ruler to straighten out any lines that should be straight (such as the center front and center back). You should have four pattern pieces, which you should label like so:

• Front
• Side Front
• Side Back
• Back

When writing your labels, make sure that the tops of the letters point to the tops of your pattern pieces; I can’t tell you how many times I lost track of which side was the top before I started doing this.

Step 14Trace the Pieces onto Muslin

One by one, trace all of the pieces onto your muslin. Using your clear gridded ruler as shown in the photo, add a 1-inch seam allowance around all of the edges except the bottom. You can skip adding a seam allowance to the top and armholes if you’re making a strapless dress like I am.
Make sure to place your pieces on the grain of the fabric correctly. That means the center front and center back lines are placed exactly parallel to the selvedge. The side front and side back pieces will be more difficult to place on-grain, you’ll just have to do your best to eyeball it.
Be sure to cut out two of every piece, a left and a right. You can cut just one front piece, if you place the center front on the fold of the fabric.