If you can afford it, going with a vintage bathroom is a must. Your bathroom is your own little self expression to all who enter. The helpless romantic may want to opt for something of the Victorian era, while a fan of rock may choose something from the 5o's or 60's.
When it comes to decorating in vintage style, start by focusing on your key interests or hobbies. Once you have your idea, run with it.
Did the earlier mention of Victorian style catch your eye? If so, you'll absolutely want to start with the curtains, aim for thick, laced, and of course elegant. Surround the bathroom with essential oils and some gorgeous candles, with decorative doilies on the counters. The most important thing to be aware of with this style is layering. And if you really want to get in the spirit of things add a pedestal sink.
With a little research you will find that companies are now reproducing deco items from the 20's and 30's. A reproduction is of course much cheaper then the original. But if you can afford it and want to be real about your vintage style, scope out the original pieces for your bathroom
Be sure to keep the bathroom tile true to the era you've chosen. Again, if money is a n issue here you can by easy stick tiling to cover up the old floor. It's cheap and surprisingly easy to install.
Now if your choosing the latter of my two opening suggestions, Rock and Roll, then I have one word for you, plastic. Plastic was in back then, end I mean everything should be plastic, right down to the shower curtains.
There are obviously many more vintage styles to choose from then what was mentioned here. A great way to get some ideas is to visit some local garage sales or flea markets. Not only may you become inspired but chances are you'll pick a few pieces to get started.