You may have heard about a hundred other voices telling you that "what someone chooses to wear is none of your business." This is usually accompanied by pictures of a variety of women in different outfits, all rocking their respective choices. However empowering this may be, I've found that few actually take it to heart. The problem is that there are whole groups of people who get overlooked in this narrative. We've somehow managed to portray this idea as one that seemingly only applies to women, and only when they choose to dress femininely.
The main problem I have when addressing this issue is that many people are quick to accept what I'm saying, then unknowingly dismiss my argument through their actions only minutes later. Often the same people who empower women to dress as femininely as they want are the same people who will criticize them for presenting as androgynous the next day. Why is one more acceptable than the other? There is absolutely nothing wrong with either. These are the same people who say that "dresses are for everyone," but who silently grimace at men in skirts; yet, most people would still agree that everyone should dress in a way that makes them happy and comfortable.
This can be easily conceptualized, but the problem lies in our society. We've been conditioned to see both gender and presentation as binary, rather than a spectrum. Many ideas of how certain genders should present have been so ingrained in our culture that even the most progressive people find it hard to dismiss these prejudices. Even worse than that are those who believe themselves to be free of guilt here, but who slip up on a regular basis.
So how can you remedy this? Simple. Just don't make negative comments about the way anyone is dressed. This applies to women, men, neither, and everyone in between. It's really not that hard to just ignore them and go about your day. If someone is dressed in a way that suits them, it's no one's place to try to "correct" them in order to force onto them different ideas of presentation. Even if you catch yourself thinking these negative comments, take a minute to stop and mentally correct yourself. You'll slip up every once in a while, but conditioning yourself to see everyone positively is the easiest way to start shedding your social prejudices. Believe me, your friends will thank you.