Ensure that your mason jar and figurines are well-cleaned before starting this craft. To get a good shine on glass, trying holding it above a steaming mug of hot water and polishing with a clean cotton cloth.
If using ornaments, remove the string. (You can leave the eye hook in place or remove if desired.)
First, check to see if your figurine needs a boost to have good visibility when the mason jar is closed by placing the figurine in the jar lid and closing the jar.
If you think the figurine needs some boosting, glue a bottle cap to the inside of the mason jar lid first before attaching the figurine.
Securely glue the figurine to the inside of the mason jar lid (or to the bottle cap, if using) and let dry. (Read the glue instructions to see if they suggest letting the glue cure for a longer period of time.)
Add distilled water to your mason jar and stir in the glycerin and glitter.
You may want to experiment with your first snow globe to see what ratio of water to glycerin to glitter you prefer. Too much glitter will make it hard to see what's in your snow globe, and too little glycerin will make it so the glitter just drops when the jar is shaken.
Personally, we used about 3/4 cup of water, 3 teaspoons glycerin and 2 teaspoons glitter.
Don't fill your jar too much because the figurine will displace some water and you want a small air pocket to allow for the shaking.
Place the inverted mason jar lid on the jar and secure tightly. Glue the jar lid in place and embellish as desired with ribbon, etc.