Listening to: Patrick Ball's The Butterfly
Just don't do it. Seriously.
This is a popular thing to do in photography and digital/traditional art, but it's all a bad idea for various reasons.
First, the entire idea of a "modern" interpretation of a geisha's look is predicated on the idea that geisha haven't evolved their look at all for a long time. Geisha don't wear the exact same style of clothing they did hundreds of years ago. They don't even wear the exact same style of clothing they did eighty years ago. Even if we were to just talk about Kyoto geiko, the inclusion of son-nari (aka wearing their kimono's excess hem tied up, with western makeup, and a chignon instead of a traditional Japanese hairstyle) is a pretty big sign that there has been some change in how geisha style themselves. But if you were to get particular about it, stylistic choices in kimono designs and in the kitsuke (how the kimono, obi, and accoutrements are worn) have also changed just in the last eighty years. Design choices in fact change all the time. Kimono fashion is not dead, even for geisha who by all accounts are not exactly radical in their design choices. A geisha of the fifties does not look like a geisha of the seventies who does not look like a modern-day geisha, unless all you care about is the fact that they're wearing a kimono. So the idea that artists need to "modernize" geisha is arrogant because they're already modern. Even a geisha in her most traditional clothing is still wearing a modern rendition of an old look. They are not wearing historical costumes.
Second, when people make a "modern" interpretation of a geisha's look, they always do it by adding Western elements and sexualizing geisha with Western sexual markers in the fashion and/or pose. Seriously, why do people say "modern geisha" when they mean "a sexy pin-up in a Western dress that has some vaguely kimono-esque design elements"? Too wordy? Well it's the truth. The thing is, it's not like there isn't a mind-set in Japan that has survived since the Meiji period that modern=Western, and between 1868 through the mid 1930s, geisha navigated this mindset and what it means for them before deciding that their image isn't "modern"... aka Western. But during that time, they did pick up a lot of Western things that they decided to keep even when they decided to eschew Western style. They picked up Western hairstyles, Western accessories, and Western make-up just to name a few things. So frankly there's no need to add extraneous Western elements to their look, because geisha have already decided which Western elements they like.
And third, and frankly most importantly, it is not some random artist's job to design and define geisha for them when they're still here. How exactly do you "interpret" a real person without fundamentally removing their ability to define themselves? Geisha are not a figure from the past to be used as a starting point for your latest piece, to be used as an "idea" or to serve as a muse for your latest interpretation of sexualized womanhood. They're real people, who live here and now and are perfectly capable of interpreting themselves. The image they present now is how they want to be presented. Why are you going out of your way to change that?
So, in summation, stop doing this.