Really great article about this cliche' expression https://spin.atomicobject.com/2017/11/01/dont-fake-it-til-you-make-it/
Maybe the subtext of this overused expression should be that you should essentially dress for the job you want. If you want to be taken seriously, take yourself seriously. Apply for the juried exhibition or juried festival. Set up that etsy shop. Upgrade your website. Reach out to more businesses. Act like you are worth it and hopefully over time it won't feel like faking it. #impostersyndrome