A balanced mix of light sources is what creates a relaxing atmosphere. Layered lighting refers to combining the three different types of lighting: ambient, task, and accent.

Ambient Lighting: This includes the general illumination of a room, which is usually through ceiling fixtures or recessed lights. Apply dimming options in order to control brightness and set the tone calm.

Task Lighting: Focused lighting for certain activities, such as reading or putting on makeup. Employ softer light sources, like adjustable desk lamps or vanity lights with warm bulbs.

Accent Lighting: Decorative lighting, highlighting specific areas or objects. String lights, wall sconces, or even LED strips can create coziness and invitation. 

The color temperature of your light bulbs plays a great role in mood-setting. Measured in Kelvin, different temperatures create different effects: 

Warm Light (2700K-3000K): Emulates candle radiance and should be used only when one wants to relax.

Neutral Light (3500K-4100K): A balanced light for general applications.

Cool Light (5000K-6500K): Great for focused tasks but not ideal to relax under.

For spa-like ambiance, remain with warm sources of light that emit a soft, golden glow.

Setting the mood, quite literally, is what dimmers are for. Dimmers let you change the intensity of your lighting to suit the time of day or your activity. Smart lighting systems can take it one step further by allowing you to control the lights through your smartphone or voice commands. Some even enable you to change the color and brightness for your ambiance.

Natural light is soothing and can elevate your space immensely. Let in as much natural light as possible by not blocking the windows with furniture, using sheer curtains that allow soft sunlight into the room. At night, for relaxation, use warm, indirect lighting to simulate natural light.

Candles spell relaxation. Their flickering light and subtle glow are essentially the reasons for the intimacy in an atmosphere. Choose unscented candles for a minimalist feel or opt for aromatherapy candles with soothing fragrances such as lavender or eucalyptus scents for an added benefit.

Adding some pendant lights, lanterns, or salt lamps for decorative lighting gives your space character. These items not only provide light but are also design pieces in their own right and, thus, can be used in a spa-like retreat.

The use of lighting would not show too much shadow or glare to keep the space calming. Use diffusers or frosted bulbs, which help soften light and disperse it, making it not so concentrated.

Lastly, bring in your personal touch with the lighting. This can be color, your favorite lamp, or custom lighting design-personal elements make the space yours.