As law is strict in the entire UAE, don't do anything which could harm anyone or is offensive. Never drive without a driving license. And never over-speed your vehicle as the roads are being controlled by radars.
As Umm Al Quwain is a Muslim city, don't eat/drink in public in the holy month of Ramadan.
Also, appropriate clothing must be worn at all times anywhere in the UAE. You don't want to attract unwanted attention.