Sewing the asymmetric top
Sew the side seams
First, match the sides of the front and back right sides together. Sew the side seams. I’m using a serger here, but feel free to use a stretch needle in your regular sewing machine with a narrow zigzag stitch (see here about the best stitches for knits).
Bind the armholes
Next, we need to bind the armholes. If you need to, seam two pieces of binding togther. Press the seam open if you needed to do that.
Next, we need to sew the binding to the armholes. We’re doing this the lazy, no-measure method I talk about in 4 pro ways to sew a t-shirt neckline.
sew binding to the armhole 
press raw edge of the binding to cover the seam 
flip binding to the inside 
topstitch binding in place
Match the raw edge of the binding to the armhole, right sides together and start stitching it to the armhole. Stretch the binding as you stitch. Make sure that you stretch only the binding, and you need to stretch it until you feel a small tug on the jersey. If you feel like you’re yanking on it, you’re pulling too hard. If you can’t tell, you’ll know you’re pulling too hard if you get little puckers on the armhole from the right side.
Repeat for the second armhole. Cut away any extra binding if you have it.
Press the seam towards the raw edge of the binding. Next, fold the raw edge of the binding so that it covers the stitching. Press the fold. Finally we’ll finish this press fest by flipping the binding totally to the inside of the top.
Topstitch the binding down with a twin needle or coverstitch from the right side. Repeat for the second side.
Sew the neckband
This is a little more advanced neckband. Because this is a raglan top, the neckband would normally cover the top of the sleeve. Since we’re going sleeveless here, we need to calculate where exactly the neckband is going to go. That way it’ll sit evenly between the front and back pieces.
Before we get there, seam the sides of the neckband together. Press the neckband in half widthwise.
Marking the neckband
Next, bring the seams together. These will be the centers of the shoulders. Let’s find that spot on the pattern.
First, measure the length of the neck seam on your front and back pattern piece. I’m measuring in centimeters here to make the next step easier. Multiply each of those numbers by 0.9 (or subtract 10%–whichever is easier for you to think about).
For example, my back neck is 7.5cm. So, I’m subtracting 0.75 cm or 6.75 cm.
Mark your adjusted length away from center front. Do the same for the back. Your neckband should look like this.
fold shoulder markings together 
mark center front, back, and shoulder markings
To find the center of the shoulder, fold the pattern piece together at the marks. Now line up the neckband seams with that fold. Mark the front neck and back neck on both sides of the neckband. I used two different colors so I wouldn’t get confused.
Stitch and finish the neckband
With right sides together, match the center front and center back to the neckband. Also match the neck markings to each edge of the front neck and back neck.
match centers and shoulder markings 
press 1/4″ towards the neck seam 
fold pressed neckband edges together
Sew the neckband to the neck. Even though there’s only 1 layer at the sides, still stitch through the neckband with the same seam allowance.
Press the seam towards the neck. Make sure that you press up the same seam allowance on the sides of the neck.
Press up 1/4″ on the raw edge of the neckband. Bring the pressed edge to cover the seam.
Pin the neckband edges together all the way around the neck. Stitch through all layers to secure the neckband and finish it.
On to the hem and making a pair of crispy mitered corners!
Elizabeth Farr is the writer behind the Elizabeth Made This blog where she shares helpful sewing tips, step by step sewing tutorials and videos to help you explore your creativity through sewing. She has written sewing Eguides and patterns, been a featured teacher at Rebecca Page’s Sewing Summit and Jennifer Maker’s Holiday Maker Fest and her work has appeared in Seamwork and Altered Couture magazines. She also created a line of refashioned garments for SEWN Denver. When her sewing machine isn’t humming, she’s playing and teaching violin, and hanging around a good strategic board game with her husband and 4 kids.