First, I'd like to say that what is perceived and/or considered as "feminine", "masculine" or even "androgynous", is 100% cultural. It's not universal, and it's totally linked to gender roles and stereotypes.
That being said, I'd say it depends what your goal is here.
Is it to see how it's like to be perceived :
- as androgynous (and make people wonder what your gender is... yeah because people tend to do that all the time lol, it's like the n°1 hobby, at least in occidental cultures..),
- as a girl.
- as a feminine boy.
Femininity doesn't limit to make up, nail polish, dresses and long hair.
If you like things like that, well, of course you can definitely go there and find what feels good for you in these areas.
But it can be a lot more subtle than that.
For instance : odors. (and not Hodor :p). Smell is the first thing that brings unconscious images to mind. And even without seeing you, people can have a representation of you from what they smell.
So using fragrances, perfumes, deodorants associated with femininity can have a lot more influence that you may think. If you like that :)
You can try clothes designed for women. Differences can be subtle but enough to modify what they "bring into light" on the body. Clothes designed for women are cut differently and can help you be more androgynous.
That can seem dumb, but even trying underwears associated with an other gender than the one you were assigned to can be (or not !) a way to express your gender. Of course, nobody will see it except yourself, but it can help building your confidence to express your gender more freely.
Haircuts can help too : if you feel confident enough, it's totally ok to ask for a cut seen in the magazines presenting women haircuts.
Using props like breast prothesis, wigs etc can be pretty expensive and I'm not sure it's what you're looking for, but that's some possibilities.
If you've got a prominent adam's apple, using a scarf can hide it.
Another (sexist hmhm) thing typically/often associated with femininity is being hair-less.. :/
But clearly, most of androgynous look comes from things you don't have control on, like how broad your shoulders are, how tall you are, the shape of your face etc.. and most of the time, androginy is very white centered (the classic image of "what is androgynous" is a thin white young body... :/).
And a big part is in other people's power : if they want to see a guy, you could go out in a dress, high heels and make up, they'll still perceive you as a guy...
The most important thing here is to experiment what you want to, how you want to, depending of what you like, what you dream about doing, and of course what you can do while feeling safe doing so.
I guess if I was to give you an advice, it would be to take it slowly, and subtly.
There are lots of things that as a role in the way people perceive one's gender. Lots of things come from body language : the way to walk, the way you move, you talk etc.
You're free to experiment whatever you feel like trying, and change your mind, and see what works for you and what doesn't, and try again, keep things and let others out, etc :).
I guess the only thing to keep in mind is that you're trying to express yourself, not looking like someone else or fitting a stereotype of "what people consider as feminine / androgynous"... or else you may end up losing yourself in the process :/
Hope that brings you ideas, and have fun experimenting :)