Ayu started a group on Facebook for her sewing buddies to share their projects and knowledge with each other to encourage each other to sew more. It's a no-pressure sort of group and I enjoy being a part of it :D
I made a tshirt for my husband a week back and someone asked how was the collar done. I used the stitch in the ditch technique, and here's a simple tutorial explaining how it was done. I think this technique is similar to attaching a bias tape as well.
I'm using cotton pieces for this tutorial, but this technique can also be used for the jersey material that the tshirt used.
The floral piece represents the collar piece, and the solid colour fabric is your shirt piece.
(Note: For tshirts, since you'll be working with stretch fabrics, your collar piece will usually be 2/3 (two thirds) the measurement of your collar hole on your tshirt.)
The colour of the thread should be as matching to your fabric as possible. That way, even if your stitch is not that perfect, it's hokay coz people probably won't see it heheh. I'm using a different coloured thread here so it's easier to see in the pictures.
Please click on the pictures for larger versions. Sorry for the messy pics, and hope it makes sense!