We made this for ourselves, so we didn't include a gift tag. However, if you're making this as a gift, you can absolutely attach a gift tag. Tie a bit of twine to your gift tag, then tie that around the mason jar. What would be really cute is if you cut a gift card in a shamrock shape and really kept with the St. Patrick's Day theme. I wouldn't do any decorating other than that to the lid of the jar or the jar itself. Adding some Mod Podge and gold glitter would be cute, but it wouldn't be food safe and your recipient might not actually be able to eat your treat.