In the past luxurious master bathroom were for the select few. Due to the availability of affordable material. However, in recent years people have choices, lower price tag, and cheaper labor. But what has stand the test of times or style is that they need to create a comfortable and enjoyable look and feel.
First, lets start with the most important and least expensive thing to do, which is always keeping the bathroom clean and clutter free. And that's doing a DEEP CLEANING. Just that in itself most of the times is a huge make over.
Even though it doesn't seem like much but adding ACCENTS, AMBIANCE, & SCENTS is another inexpensive touch that changes the mood and gives a huge return. Make sure the counter top accessories, towels, mats, and even faucets & hardware have a similar theme/look with a touch of color to give it a visual flow. A quick and non cluttering way to add some ambiance is to set a few candles and plants/flowers. And when dealing with scents it's light and airy (ie. small scented soap, a couple of scented reeds, or a little potpourri) so don't even think of using cologne or perfume as a alternate. Just make sure to know less is best in this tip.
Having AMPLE STORAGE is a very tricky update to a bathroom. You still have to make it look neat while having enough to be functional. Too much will be counter productive and make the room seem smaller. When I speak of expanding space it's directly adding some cabinets and decorative shelves, not loose stacked baskets and closet/garage hangers/shelves.
Dramatic LIGHTING & COLOR is one of the top 2 "wow" factors. Neutral is best for a color choice and try to stay away from wall paper for resale. As for lighting consistent, bright, and in tune with the decor. You would be surprised what lighting can do to any room.
And the biggest factor and most costly one is the CABINETS, COUNTER, & VANITY. The biggest eye catching factor of most and many. It sets the theme and gives a home a quicker resale, but if you go overboard dont expect a full return on this investment.
So with all this being said I hope that a few of these tips may help you in either making your bathroom feel calming or aid in receiving a higher offer during your listing.