The best cure to a stressful day (or week/month/year/life) is almost always a visit to the spa. So, why not create one at home?
Decorate using a calming color palette.
Choose a soft, relaxing color palette when thinking about your bathroom decor. Whites, blues, and blush pinks come to mind for me. Let this color palette be carried through all of your decor from the shower curtain to the towels and accessories. To keep things visually interesting, experiment with varying textures. For instance, selecting an all-white color scheme could mean that you have a white ruffled voile shower curtain, white marble soap dispensers, and white Egyptian cotton bath towels.
Transfer your products into beautiful storage containers.
Empty products such as cotton balls and q-tips into glass apothecary jars, discarding the generic plastic bags in which they're sold. Unless the packaging is really beautiful (i.e. Aesop, Byredo, Ouai, etc.), consider transferring your soap, lotion, and shampoo into glass dispensers.
Invest in a fluffy, monogrammed bathrobe.
I think that putting on a robe is the quickest way to feel as though you're actually at the spa.
Gather an aromatherapy arsenal.
I recommend three types of candles for the optimal bath sanctuary. The first is an unscented pillar candle in a lantern to create relaxed low lighting. The second is a smaller candle in your favorite relaxing scent. The third is a collection of tealights to scatter around the room for added effect. For added aromatherapy benefits, use twine to tie sprigs of lavender and eucalyptus around your shower head.
Hide away your clutter.
Keep your space clutter-free by storing products in the medicine cabinet and dirty laundry in a nice basket hamper.
Keep things clean.
This is the most important point. You don't need luxury bath products and Egyptian cotton robes to have a relaxing bathroom. But, it is pivotal to have a fresh-smelling, clean bathroom. Splurge on a high-end cleaning product and use it often!