Cut a piece of watercolour paper to your desired size. Secure it to your working surface (such as a baking sheet) with painter's tape.
Add a dot of red acrylic paint wherever you'd like your rainbow to begin.
Repeat, adding the remaining colours of the rainbow (orange, yellow, green, blue, indigo, violet) in a row so that the dots touch.
Step 3: Squeegee the paint
Place your squeegee down below the paint and hold it firmly on the paper. Move it in the direction you'd like the rainbow to go (straight, or in an arch).
Continue until you reach the edge of the paper.
Remove the tape and lift the paper from the tray.Set it somewhere it won't be disturbed and allow to dry for 10 to 20 minutes.
Step 4: Decorate the painting
Pull a cotton ball apart to make to make a puffy cloud.
Add a small amount of glue below the rainbow and press the cloud into place.
Add dots of clear glue on top of the cloud.
Sprinkle glitter over the cloud, making sure to cover all the glue.
Lift and tilt the paper to let the excess glitter fall off.