The first and one of the most important elements is to make the space personal and unique. It is not your master retreat; however, it is still a bathroom in your home and you want the design style to reflect that. Do not be afraid to use colors and textures that really speak to you. The main challenge when it comes to a smaller space is the actual configuration of the sink, toilet and in some cases, the shower.
So when it comes to the placement of the sink and vanity I have two suggestions for you. The first one is to install a corner sink. Often times guest bathrooms have a small walkway and it can be an annoyance if there is a vanity right in the middle of that walkway. If you do not want to put the vanity in the corner, another option is to choose a rounded vanity. Not only will a rounded vanity save your hips from bumps and bruises it offers a unique design addition to the space.
If it is a guest bathroom you are redesigning it might have a shower or bathtub or shower combination in it. I recommend if it is a smaller space to opt for a shower curtain. You will not have to worry about which way the shower door swings open and it can be tucked into the shower so it is 100% out of the way of the walkway.
Lighting is especially important when it comes to creating more space in a bathroom. I am sure you are going to add vanity lighting over the mirror but have you thought about maybe adding under cabinet lighting?
I know some people believe that wallpaper is outdated, but I appreciate it's traditional style! There are some wallpapers that still hold their worth in today's design world. When you are working with a smaller space if you add wallpaper with vertical stripes it almost gives the space a sense of height. It tricks people's eyes into thinking the ceiling is higher than it actually may be.
Smaller rooms are often a challenge when it comes to designing but I hope some of these tips help you out on your next design adventure. If you have any design tips to share, I'd love to hear them!