This FAQ shows with video and text, guidelines, tips and tools for embroidering children's items. When we are dealing with children's items, we have special concerns such as placement on small items and covering the backside of the embroidery for delicate skin.
This video with Eileen Roche and Ashley Jones covers some of those concerns:
In the video, templates from the Children's Perfect Placement Kit are recommended and demonstrated. It is also possible to create your own templates. Print & Stick Target Paper is a useful item for doing so.
Shirt:
Covering the Back
Whatever you are embroidering for children, you might consider covering the back of the stitching. A fusible light weight interfacing is a suitable choice. In this video,Exquisite Fuse-so-Soft is recommended and demonstrated.
When you look for something to cover the back, you want something with a soft drape, so it won't distort or otherwise change the feel of the garment. You also want it to be fusible, and permanent through repeated washings.
After embroidery, use a dry iron and fuse it over the back of the embroidery. This is a good practice for most wearable items, when the backside of the embroidery is likely to be against the wearer's skin. This is especially the case for sensitive skin, including kids' skin. An additional perk to using a covering like this on the back of embroidery is that it can keep the stitches from coming undone, even if you accidentally snipped the knot.