"Over-sized mirrors in bathrooms are also a great way to pass as much light around as possible and give the impression of a larger space," says Cotter. "I'd also suggest investing in a more expensive tile, so the mirror can showcase it twice."
She takes her clients' shower glass up higher than standard height to elevate the look and feel of the bathroom.
"Designers are starting to call bathrooms 'wellness spaces' and they're starting to take on more importance in the home," says Cotter. "Open-plan living has reduced the spaces you can take time out from the rest of the family, so the bathrooms of tomorrow will replicate the feel of a day-spa to help you relax."
So often, bathrooms have become lost opportunities, but they don't need to be
To turn your bathroom into a wellness space, think about finishes - such as using textures, layering surfaces and using more timber to add warmth. There are also now tiles that are made to look like timber. Audio is another important consideration to give a natural spa-like atmosphere, so include music in the bathroom design.
"Think about spaces in the bathroom you might be able to rest a glass of wine, cup of tea, your iPad or a book," says Cotter. "Seating in bathrooms is also becoming more popular as a way to create more of a wellness space."
Current trends include the use of colour in sanitary ware, such as toilet bowls and bathroom sinks.
"Blacks and charcoals, as well as a new blush tone, are coming through in sanitary ware," says Cotter. "There's also a use of mixed metal, rather than just bright shiny chrome, in tapware. For example, stainless steel, black, copper and brass finishes."
Bathrooms are being seen less as utility spaces and elevated with items such as decorative tiles - often on the floor to create the look of a rug - all with the aim of creating a space you want to sit in and enjoy.
Technology is also advancing in bathroom design, with finer porcelain being produced that has a more sophisticated feel. There's a trend towards streamlined design rather than heavy, chunky items.
"I like the idea of doing the unexpected in a bathroom," says Cotter. "For example, a tile supplier is bringing out a tile that looks like woven fabric, that could be really interesting in a bathroom - it's a ceramic tile that looks like linen and is stunning."
There's also tapware with jets to create a steam room in the shower and a bathroom that can analyse your health, including your weight and temperature.
"You'll be able to brush your teeth and the toothbrush will take samples to make sure you're healthy," says Cotter. "Health monitoring is the grand plan for future bathrooms."
To give your bathroom the spa-like feel, lighting is important and can include strip lighting under vanity cabinets. There's a trend that people want to drop down the lighting at various stages of the day, so different lighting options are increasing in importance.
"LED lighting has also opened up the way we light a bathroom so that we can now incorporate darker colour schemes," says Cotter. "I really love the idea that bathrooms are a bit more of a secluded sanctuary than the bright light clinical bathrooms of the past."
There's also a trend towards having green elements incorporated in bathroom designs, for example, a small courtyard big enough only for a wall of bamboo or a small tree that forms one side of the shower, or using photographic wallpaper featuring green elements, such as a rainforest, along one wall.
In more practical terms, Cotter advises hiding away items such as electric toothbrushes by placing power sockets inside mirrored cabinets. She says having tapware coming out from the wall is a way to make the vanity top easier to clean.
"People used to say that a bathroom should last the life of your house, but we're all updating our homes more often than ever before so now it's about every 8-10 years," says Cotter.
"The bathroom is a really hard-working space and items can't easily be replaced, so buy the best products you can afford."
Create an oasis of calm in your bathroom and it may do you and your home a world of good.
TOP TIPS
*Multi-task your spaces.
For example, a mirror can hide a power unit and storage cabinet.
*Create a wellness feel to the room through the use of timber for warmth and layering of textures.
*Add music, candles and soft lighting to increase the appeal. Research the most economical and up-to-date water systems and sanitary ware and buy the best you can afford.
*Call in the experts: Everyone deserves to live in a home they love, so interior designers often work on one room at a time to provide a more affordable option.