There are lots of different things you can do to design a bathroom that works for you and is nice to look at. Here are some of the things to consider:
Shower and Bath
There are so many different shower and bath styles to choose from. You'll want to decide up front whether you want a tub at all. You can save a bit of space by having a shower-only stall put in. Choosing this option doesn't mean you have to forego luxury either. You can have a full "body spa" installed in your upright shower. These don't just have the one showerhead that rains down water from above. They have adjustable jets that send out water at all levels, massaging and relaxing you as you get clean. You can also add in a steam shower option to take the soothing comfort to the next level. Some showers are even offering "chromatherapy," shining small streams of color through the water and adding a visual component to the relaxation. Some of these options are available with a tub as well. And with a tub you can also get spa jets that allow you to lie back and relax in style.
If you've got the space, you may want to consider two sinks. You can keep all your things by your own sink and your significant other can use the other sink without interruption or competition. Most sinks feature a porcelain bowl which can be colored to match the rest of the decor in your bathroom. The faucets can be a simple silver color, or for an extra dash, you can get them in brass. Your local home store will have all sorts of handles for you to choose from as well.
It is a truism of home design that mirrors extend the space you live in. This can be particularly true in a bathroom, which is often a rather small room. The more area you can cover with mirrors, the larger the room will seem. For grooming purposes, it's also helpful to have mirrors that face each other and are at angles to each other. This makes it easier to see yourself from all sides. Don't just put a mirror on the wall above the sink. Put a mirror at the corner wall and on the wall facing the sink as well.
One of the trends in bathroom design is toward recessed lighting. This can provide a warm, gentle light; but there's also a potential problem. If the lighting doesn't stick out past the edge of the mirror, the mirror itself will be in shadow. As you choose lighting, remember to think about where the shadows will fall and adjust your plans if the shadows will end up being in places that you really need to have lit up.
Carpeting can absorb moisture and lead to mildew. So most bathroom floors tend to be of other material. You can have hardwood floors that have been treated to be moisture resistant. Or you can linoleum or tile. Any of these can be uncomfortably cold to the feet on a winter morning. The usual solution to this is to thrown in a bathroom rug to step on. But there's a higher tech solution available as well: heated floors. You can actually have your floor installed with a heating element underneath, making it completely cozy and comfortable to the touch.
Your home store will have a wide variety of cabinets to choose from as well. You can choose ornate or plain in many different styles. A cabinet is a natural place to have an extra mirror in the bathroom. The door can even be angled, allowing you to adjust the mirror to work in conjunction with the mirror over the sink and show you from different sides at the same time.