Well, awhile back, and I know a lot of people don't know this still, Plaid released Mod Podge Sheer Colors. This is a very specific Mod Podge formula with added color (and comes in several shades) that is used for this very purpose – tinting glass.
There are many ways to incorporate the Sheer Colors into your crafts, but I'm really loving the way Morena did it with her fall display above. If you have yet to try the Sheer Colors, click below and learn more. You'll be addicted!
How to tint glass with Mod Podge at Crafts Unleashed