I've been misgendered quite often over my life. I'm interested in how other biological women handle it as I'm sure I'm not the only one this happens to (might be a very short thread if I am)
Note. This post is not intended to look at how TW handle it or how we think they should. I'm not deliberating excluding them but there's been plenty written by TW on misgendering and I'm interested in the biological woman's perspective as the problem is not unique to trans women or trans men.
For background I have quite strong facial features and shortish but feminine styled hair, I also have a very obviously female physique - Am I allowed to say that here?
I've been misgendered on occasion since I was a child, (like most children when I was growing up I wore gender neutral clothes) even happened when I was heavily pregnant 
Sometimes it's been very deliberate to make the point they felt I was (unwelcome) in a male (work) environment and the intention was to exclude me.
Sometimes it's been rudeness, using gentlemen for example because predominantly men in the room and can't be bothered to adapt for women present
Sometimes it's accidental, service personnel calling me sir when they are addressing me directly.
Sometimes it's patriarchal for example official correspondence that starts Dear Sir because they assume they are addressing a man. Which annoys me.
I've never been entirely sure how to handle it. For service personnel I assume it's accidental and blink slightly as I've been female since birth and don't have a deep voice, Then I go with it and hope they don't get embarrassed when (if) they realise they've made a mistake.
In a group situation where they are referring to gentlemen I sometimes flag that there is also a lady present to make the point that they are being exclusive but sometimes it's just not worth it, I think this is the only time I correct people.
Letters I want to write something along the lines of 'women exist too' and return but life's too short.
To (possibly mis)quote an Alison Moyet song, 'It makes me feel like I'm invisible'. It isn't that I personally feel invisible but I feel like women are invisible 