There are two parts to a person – his neshama and his guf. The person’s essence is his Neshama. His guf isn’t him; it’s just a tool that Hashem gave him to enable him to do things.
If people are giving you attention because of your guf, that has nothing to do with you. They are ignoring you and focusing on your guf instead. That means they don’t really care about YOU.
If people really appreciated you, it would be “you” that they give attention to – your personality and middos and thoughts, NOT your guf.
If you are trying to get attention by dressing untziusly, it means you are not connected to the “Real You” – the things that make you unique and special.
You should try to work on figuring out what your “maalos” and strengths and talents are, and find ways to develop them and to “get attention” for those things. Even then, it shouldn’t be “attention” you are trying to get as much as “appreciation”.
I’m sure you have many wonderful qualities – you sound like a sweet, sincere person. Maybe you should work on appreciating your many fine qualities, and then you won’t have a need to dress untzniusly.
It also sounds like you may need to change your friends and the crowds you hang out in. Find people who appreciate others for their inner qualities – the real person.