According to the website kitchenandbathideas.com, "An en-suite bathroom is one that is directly connected to the bedroom and is usually featured in the master bedroom in homes with several bedrooms."
It is an investment, which, if executed well, will increase the value of your home, not to mention, allow a greater level of convenience. Your bedroom will be a place of total repose; you can easily take a long bath, and then sink into bed.
Floors and Ceilings
If possible, try to install the same flooring from the bedroom in the en-suite bathroom. By having the same flooring throughout, you create a seamless feel that's more pleasing to the eye.
Also, if possible, try to lower the ceiling in your en-suite bathroom. Most en-suite bathrooms simply don't have the luxury of space, and a high ceiling in a cramped bathroom makes the room feel even more cramped and claustrophobic.
Installing what luxuries you possibly can into the new bathroom will help not only your investment but enhance your day-to-day life.
For example, if you can fit a tub into your en-suite bathroom, consider installing a whirlpool tub. If you only have room for a shower, install a top-of-the-line spa-like shower head. Hang a large, elegant mirror with an eye-catching frame that matches your decor. The large mirror will not only reflect light, but will reflect space as well, making the area feel bigger.
The worst thing for an en-suite bathroom, or for any small bathroom, is for it to be cluttered and disorganised. Make use of all available space. For example, put shelves above the toilet, place hooks on the back of the bathroom door for towels and bathrobes, and add a shower caddie for shampoo and other products around the shower head. You literally want everything to have its place.