I have a tiny master bathroom that was gloomy until I painted over the ochre color and changed the brown cabinetry to white. The whole change was completed in a couple of days, and that was only because I needed dry time between coats of paint on the cabinets.
The most time consuming part is painting the oak colored woodwork white. A light sanding and two coats of Kilz primer for stain and tannin blocking was the first step. Between coats and drying time, I aired out my brain (there's no window in there!) by cleaning and spray painting the hardware a hammered nickle color outside. I also spray painted the mirror frame and interior. Helpful hint *use press and seal wax paper from the grocery isles to cover the mirror. That stuff is amazing! On day two, before the glossy white finish coats went on the wood, I painted the walls an antique beige (Glidden paint).
The change in color made an amazing difference in lighting. Those before and after photos are not touched up!
The ceilings were already painted a rainy day blue I just added white clouds. I like them because they make this small bedroom with no window feel a little less claustrophobic. You can easily copy this technique. Paint the ceiling a light blue then use a wadded up plastic grocery bag to dab on white paint clouds. Thicker in some spots and thinner in other spots to allow some blue to bleed through gives the clouds more depth. The pendant lamps were 1970 brass so I used some of the white gloss paint to brush on a more modern finish.
Here are some of the little decorating details.
You can see all the rest of the whole home make over here.