Start growing a little personality edge in public. Change minor things that you do to make yourself look more Tsundere.
Uni-Chan, what do you mean? O-o
For example, if you walk looking down (like I do at times) Make sure to look up, proud and tall. That way, it sends the message to people that you're not a shy person. Which is what a Tsundere isn't. When you're standing still place your hands on your hips.
Another example is the way you talk, are you quiet or loud? Don't worry about saying the wrong thing or saying something dumb, cause a Tsundere usually blames their mistake on someone else. It's also pretty funny when they do, I personally think that's what makes them Kawaii ^w^
The last example I'm going to give you is how you act when you're not around your friends. A Tsundere isn't going to call someone a baka (or idiot) just because they got a question wrong. Especially if they don't even know that person. Usually a Tsundere would be Kind/Helpful but distant. Either that, or they would be quiet and distant.
Uni-Chan, isn't that considered a loner? O_O
I mean, if you want to look at it like that. I was thinking about someone who just goes to class because they have to and rather not talk to anyone. I can imagine it pretty well. They wouldn't talk to you unless you talk to them, and when you do they would try to make the conversation short and act harsh towards you. That is, if you don't know them.
Overall, just change the little things you do to make yourself appear Tsundere. You need to appear Tsundere or else people won't know what they're getting themselves into XD
