Turn up half an inch of fabric and press, then turn up the width of your hem (I did 1.5 inches in the photographed example) and press again.
Tuck your hem under the fabric (towards the right side) so that just the ¼ an inch of the half inch hem you did shows next to the back of the fabric (as per photo below).
On your sewing machine you need to select the blind hem stitch, it will look something like stitch 10 in the image below. You need to use your blind hem foot, I’ve photographed mine below for you.
On my machine (Janome TXL607) you need to use foot G, and either stitch 0 from Mode 1 or stitches 10 or 15 on mode 2.
The black guide in the middle of the foot should lie against the fold in the top fabric as you can see in the photo above. You have to make sure you keep the guide lined up throughout to get neat stitching.
This is how the hem will look when you have finished stitching.
When you’ve finished stitching you need to fold the hem back down, and press it again.
On the right side of the fabric you will only see a few very small stitches of thread. If you’ve matched your thread well to the fabric these will be barely visible. We used a contrasting thread so you could see the stitches.
This stitch is only suitable for straight edges such as curtains and skirt or dress hems. It doesn’t work well on curves at all. It is most commonly used for curtains.