again, there are two main things i’d suggest focusing on: -studying the different parts of an armor and how they work and -visualizing the armor as 3d shapes
i found some sites that go over things like armor parts and their functions here and here, a lot of nice photo reference here, and a bunchoflabelleddiagrams on google images
there is a lot of liberty you can take with the details, shapes, and proportions etc, (also remember, medievaleuropeisn’ttheonlyera armor comes from!) so you can use that to communicate things like the time period and culture the armor is from, the personality of its wearer, etc.
with simplifying armor into 3d shapes i’d basically just use a regular human body as a base. having a decent grasp of anatomy really helps with this i think
there is technically little or no difference between actual male/female armor, from the way i understand things at least (armor is just armor after all), but you can take a look at this post of mine for strategies you can use to make armor look more masculine or feminine
and then of course there’s that boob plate thing there are reasons why those don’t really work in real life but you could always pull out the artistic liberty card so