Put on a pair of rubber gloves, because the oil on your hands will affect the finish.
Wipe the surface of the glass tiles down with rubbing alcohol and a soft cloth. Leave the tiles to dry for 15 minutes.
Paint the tiles. Pour quarter-sized dollops of paint on your paint palette. Use a small brush to create individual designs on the tile, tape a stencil on the tile and use it to create your design or paint each tile a solid color and place them next to one another in a specific order to create a larger design.
Leave the tiles to cure for 24 hours.
Put the tiles on a baking tray and place them in an unheated oven. Turn the oven to 350 degrees F for 30 minutes. Turn the oven off and allow it to return to room temperature before removing the glass tiles.
Affix the tiles to the wall with mortar. Or, hang large tiles individually using a plate hanger.