Hand sewing isn’t all that difficult for patches with borders that wrap around the edge. I use masking tape to hold the patch in place, turn the uniform inside out and sew the patch on by stitching through the raised border not the patch itself. You don’t have to force the needle through the patch, just catch the border. You can hide the stitches behind the patch this way and will only need one thread color that matches the shirt rather than the patch.
You’ll be sewing through the patch and that will require thread colors that match the patch if you don’t want the stitching to show. I prefer Badge Magic or hand sewing.
Boy Scouts can wear a merit badge sash with their uniform anytime, most choose to wear them only at special events; like courts of honor. There is no special order to placing merit badges on the sash, just start sewing them on in rows of three as they are earned. If you have an ambitious Scout who fills his sash with badges on the front you can use the back as well.
Scouts tend to accumulate lots of event and activity patches (camporees, cub weekends, hikes and trips, etc.) We call these ‘temporary insignia’. Scouts can sew one temporary insignia of their choice on the right hand pocket of the uniform shirt. Here’s a hint – if the patch in question is not mentioned in the official uniform inspection guides above it is probably a temporary insignia.
But what do you do with the temporary insignia patches, badges of rank, etc when you remove them from the shirt? Here’s some options: