Bias tape, also referred to as bias binding, has many practical applications. It is often used in garment sewing, finishing the arm holes of a dress, encasing the top edge of a pocket or bottom edge of a hem. It's also used frequently in home decor and accessory sewing to add the finishing touch to a project, such as a blanket or bag. It is very simple to apply and has a nice, clean finished look. Plus when you use a contrasting tape it becomes a fun design element.
Bias binding is also easy to make yourself so you are not limited to the pre-made, packaged tapes... virtually any cloth will do (though I suggest starting with a standard cotton weight until you are comfortable with the process). Clover tape makers are my preferred tool. They come in many sizes and the directions to make your own are easy to follow. Colette Patterns have also written a great how to make bias tape tutorial, here. When you make your own the binding the possibilities are endless; tiny flowers, polka dots, pinstripes, gingham and any color of kona cotton or a chambray. Have fun.
Here we go...
First completely unfold you bias tape. Here I am using tape I made using a 1" tape maker (ending up with a 1/2" wide binding) in a blue chambray.
Pre-made bias tape and tape made with some bias tape makers (such as Clover brand) will have one side narrower than the other. Visible when first unfolded.
Beginning with the narrower side, align the raw edge of your tape with the raw edge of your project, right sides facing. Fold the short end of your tape down at a 90 degree angle to meet the raw edges (shown above) and start sewing, backstitch.
Sew until you come to about seam-allowance distance away from the corner of your project (in my case 1/4") and backstitch.
Take your project out from under your presser foot, fold your bias tape up and to the right forming a 90 degree angle. Neatly finger press.
Then fold your tape straight out to the left along the raw edge of your base fabric. Pin in place.
Start sewing again along this second edge, seam allowance distance (1/4") in from the corner, backstitch. Note: Don't worry about the 1/4" unstitched portions around the corners. They will be taken care of in the final steps.
Continue around your entire project. When you get to where you started, continue to overlap your tape and sew about 2"- 3" past your starting point, backstitch. Cut off any extra tape.
Refold your bias tape: Flip your project over and refold your tape, encasing all raw edges.
When completely folded your tape should just barley cover your original stitch line. This is the reason for your bias tape having one folded edge slightly narrower and one thicker.
If you have a bias tape maker that does not create one side narrower then the other, you simply need to fold your tape slightly off (not quite in half) and attach the smaller side of your tape first.
Pin your tape neatly as you check to be sure all stitches are hidden underneath.
I like to use extra long flathead pins for this... the longer the pin the less pinning, plus they're cute! Also take care to tuck all corners into a tidy miter as pictured above.
The little boat print here is from Kokka's Trefle Collection (edited)
Finally topstitch, about an 1/8" from the inner edge of your tape, the entire way around your project, backstitching when your stitches meet. Voilà!
Note: You could also finish your bias binding by hand stitching the folded edge to the back of your project. This is a nice option when you don't wish to see any topstitching.