The short version is that it's really complicated and annoying. The most common workaround I've seen in French is to alternate between masculine and feminine forms ("My teacher[masc] Miss[fem] Smith is nice[masc] and pretty[fem], but sometimes too strict[masc]"), but it's clearly a workaround and not very satisfying. In Spanish the use of -x instead of gendered endings -a/-o is gaining currency, e.g., "an anthology of Latinx poets", "a collective of Chicanx artists".

It gets more complicated in languages like Japanese, where the whole way you construct a sentence and speak your words changes depending on your gender. A white male friend of mine is often asked why he speaks Japanese like a woman; it's because his teacher was a woman, and she taught him the language the way she speaks it. After a certain point you have to create an entire new way of linguistically existing. It's a challenge.