A view of water evokes a sense of relaxation and peace for many people. If that view is from under the water, add to that an almost mystical fantasy vibe. If you spend a good deal of time fantasizing about swimming, snorkeling or scuba diving, painting a room with a water theme offers a bit of the same atmosphere without having to leave the house.
Wipe the walls down with a duster to remove loose dust, followed by a damp cloth. Allow walls to dry completely.
Cover areas that are not to be painted with painter's tape, such as the baseboards or window and door trim. Push all furniture to the center of the room, or remove it completely. Place a dropcloth on the floor in front of each wall, or use newspaper.
Open and stir some of the all-in-one primer/paint using a paint stir stick. Pour some of the liquid into a paint tray. Paint the project walls with a paint roller, using a paintbrush to reach into the corners. Allow primer to dry completely.
Open and stir the darker blue paint. Pour some of it into a paint tray and stir in some glaze -- approximately 1 part paint to 2 parts glaze. The amount of glaze needed isn't an exact science, but the more glaze used, the more translucent and "waterlike" the finish.
Apply the glaze mixture to one small area of a wall using a paintbrush, working in a general horizontal direction. Brush it on in a slightly overlapping wavy pattern, if you like, copying the appearance from a reference photo of an underwater scene. Rub the glaze in and partially off using a clean cloth.
Repeat Step 5 in an adjacent area, continuing the process until all walls are glazed to your liking. Working in small areas at a time creates a consistent appearance and gives you time to rub in the glaze; otherwise it may dry out before you can wipe it off. Allow walls to dry completely.