Women Travelers - What should a woman wear during travelling in an arabian state?

In two weeks I'll be in Dubai, my very first time in an arabian state.
And I don't know what to wear.

What is allowed to wear?
What isn't allowed to wear?
What would be the biggest mistake I could make?

I wonder what kind of shoes are allowed. I don't know, if it's ok to wear a T-Shirt. Do I have do wear longsleeve blouses?

I appreciate your hints for adequate clothing. TIA.

If you are not Muslim (really, not just Muslim but a GCC national) then no one in Dubai will care at all what you are wearing. Local UAE citizens are outnumbered by something like 10:1 by foreigners--both expats and tourists--and those foreigners come from all over the world. You will see European tourists walking around in tank tops and shorts, Southeast Asian household workers wearing t-shirts and pants (and occasionally headscarves if they are Muslim), Natashas of indeterminate East European nationality dressed like the mid/high-end prostitutes that they are, professional women in Western business attire, GCC women in full abayas, etc. "Do your own thing" is the norm here. Dubai is NOT Saudi Arabia, where you really do have to conform to a very strict dress code.

If you are not Muslim (really, not just Muslim but a GCC national) then no one in Dubai will care at all what you are wearing. Local UAE citizens are outnumbered by something like 10:1 by foreigners--both expats and tourists--and those foreigners come from all over the world. You will see European tourists walking around in tank tops and shorts, Southeast Asian household workers wearing t-shirts and pants (and occasionally headscarves if they are Muslim), Natashas of indeterminate East European nationality dressed like the mid/high-end prostitutes that they are, professional women in Western business attire, GCC women in full abayas, etc. "Do your own thing" is the norm here. Dubai is NOT Saudi Arabia, where you really do have to conform to a very strict dress code.

As above - my best friend lives there, and wears what anyone in the US would wear - shorts, skirts, tank tops etc.

Thank you very much for your clothing advices.

Didn't know, that it would be so easy to be well-dressed in Dubai.
My guidebook to Dubai listed many things, that I should regard and respect.
I see, it's better to ask people who are living there or have been travelling to Dubai.

I was only there for a half a day, but I think it would be best to avoid tank tops (bare shoulders) and short skirts or shorts. Sure, it's fine to dress however you like, but in my opinion a lot of those women are insulting some of the locals. While most people living in Dubai are expats, most of those are from the Indian subcontinent or Middle East, places that value modesty in dress.